lt_probackup — manage backup and recovery of LightDB database clusters
lt_probackup version
lt_probackup help [command]
lt_probackup init -B backup_dir
lt_probackup add-instance -B backup_dir -D data_dir --instance instance_name
lt_probackup del-instance -B backup_dir --instance instance_name
lt_probackup set-config -B backup_dir --instance instance_name [option...]
lt_probackup set-backup -B backup_dir --instance instance_name -i backup_id [option...]
lt_probackup show-config -B backup_dir --instance instance_name [--format=]format
lt_probackup show -B backup_dir [option...]
lt_probackup backup -B backup_dir --instance instance_name -b backup_mode [option...]
lt_probackup restore -B backup_dir --instance instance_name [option...]
lt_probackup checkdb -B backup_dir --instance instance_name -D data_dir [option...]
lt_probackup validate -B backup_dir [option...]
lt_probackup merge -B backup_dir --instance instance_name -i backup_id [option...]
lt_probackup delete -B backup_dir --instance instance_name { -i backup_id | --delete-wal | --delete-expired | --merge-expired } [option...]
lt_probackup archive-push -B backup_dir --instance instance_name --wal-file-name wal_file_name [option...]
lt_probackup archive-get -B backup_dir --instance instance_name --wal-file-path wal_file_path --wal-file-name wal_file_name [option...]
lt_probackup is a utility to manage backup and recovery of LightDB database clusters. It is designed to perform periodic backups of the LightDB instance that enable you to restore the server in case of a failure.
As compared to other backup solutions, lt_probackup offers the following benefits that can help you implement different backup strategies and deal with large amounts of data:
Incremental backup: with three different incremental modes, you can plan the backup strategy in accordance with your data flow. Incremental backups allow you to save disk space and speed up backup as compared to taking full backups. It is also faster to restore the cluster by applying incremental backups than by replaying WAL files.
Incremental restore: speed up restore from backup by reusing valid unchanged pages available in LTDATA.
Validation: automatic data consistency checks and on-demand backup validation without actual data recovery.
Verification: on-demand verification of LightDB instance
with the checkdb command.
Retention: managing WAL archive and backups in accordance with retention policy. You can configure retention policy based on recovery time or the number of backups to keep, as well as specify time to live (TTL) for a particular backup. Expired backups can be merged or deleted.
Parallelization: running backup,
restore, merge,
delete, validate,
and checkdb processes on multiple parallel threads.
Compression: storing backup data in a compressed state to save disk space.
Deduplication: saving disk space by excluding non-data
files (such as _vm or _fsm)
from incremental backups if these files have not changed since
they were copied into one of the previous backups in this incremental chain.
Remote operations: backing up LightDB instance located on a remote system or restoring a backup remotely.
Backup from standby: avoiding extra load on master by taking backups from a standby server.
External directories: backing up files and directories
located outside of the LightDB data
directory (LTDATA), such as scripts, configuration
files, logs, or SQL dump files.
Backup catalog: getting the list of backups and the corresponding meta information in plain text or JSON formats.
Archive catalog: getting the list of all WAL timelines and the corresponding meta information in plain text or JSON formats.
Partial restore: restoring only the specified databases.
To manage backup data, lt_probackup creates a backup catalog. This is a directory that stores all backup files with additional meta information, as well as WAL archives required for point-in-time recovery. You can store backups for different instances in separate subdirectories of a single backup catalog.
Using lt_probackup, you can take full or incremental backups:
FULL backups contain all the data files required to restore the database instance.
Incremental backups operate at the page level, only storing the data that has changed since the previous backup. It allows you to save disk space and speed up the backup process as compared to taking full backups. It is also faster to restore the cluster by applying incremental backups than by replaying WAL files. lt_probackup supports the following modes of incremental backups:
DELTA backup. In this mode, lt_probackup reads all data files in the data directory and copies only those pages that have changed since the previous backup. This mode can impose read-only I/O pressure equal to a full backup.
PAGE backup. In this mode, lt_probackup scans all WAL files in the archive from the moment the previous full or incremental backup was taken. Newly created backups contain only the pages that were mentioned in WAL records. This requires all the WAL files since the previous backup to be present in the WAL archive. If the size of these files is comparable to the total size of the database cluster files, speedup is smaller, but the backup still takes less space. You have to configure WAL archiving as explained in Setting up continuous WAL archiving to make PAGE backups.
PTRACK backup. In this mode, LightDB tracks page changes on the fly. Continuous archiving is not necessary for it to operate. Each time a relation page is updated, this page is marked in a special PTRACK bitmap. Tracking implies some minor overhead on the database server operation, but speeds up incremental backups significantly.
lt_probackup can take only physical online backups, and online backups require WAL for consistent recovery. So regardless of the chosen backup mode (FULL, PAGE or DELTA), any backup taken with lt_probackup must use one of the following WAL delivery modes:
ARCHIVE. Such backups rely on continuous archiving to ensure consistent recovery. This is the default WAL delivery mode.
STREAM. Such backups include all the files required to restore the cluster to a consistent state at the time the backup was taken. Regardless of continuous archiving having been set up or not, the WAL segments required for consistent recovery are streamed via replication protocol during backup and included into the backup files. That's why such backups are called autonomous, or standalone.
lt_probackup currently has the following limitations:
The remote mode is not supported on Windows systems.
On Unix systems,
a backup can be made only by the same OS user that has started the LightDB
server. For example, if LightDB server is started by
user lightdb, the backup command must also be run
by user lightdb. To satisfy this requirement when taking backups in the
remote mode using SSH, you must set
--remote-user option to lightdb.
The LightDB server from which the backup was taken and the restored server must be compatible by the block_size and wal_block_size parameters and have the same major release number. Depending on cluster configuration, LightDB itself may apply additional restrictions, such as CPU architecture or libc/libicu versions.
Once you have lt_probackup installed, complete the following setup:
Initialize the backup catalog.
Add a new backup instance to the backup catalog.
Configure the database instance to enable lt_probackup backups.
Optionally, configure SSH for running lt_probackup operations in the remote mode.
lt_probackup stores all WAL and backup files in the corresponding subdirectories of the backup catalog.
To initialize the backup catalog, run the following command:
lt_probackup init -B backup_dir
where backup_dir is the path to the backup
catalog. If the backup_dir already exists,
it must be empty. Otherwise, lt_probackup returns an error.
The user launching lt_probackup must have full access to
the backup_dir directory.
lt_probackup creates the backup_dir backup
catalog, with the following subdirectories:
wal/ — directory for WAL files.
backups/ — directory for backup files.
Once the backup catalog is initialized, you can add a new backup instance.
lt_probackup can store backups for multiple database clusters in a single backup catalog. To set up the required subdirectories, you must add a backup instance to the backup catalog for each database instance you are going to back up.
To add a new backup instance, run the following command:
lt_probackup add-instance -Bbackup_dir-Ddata_dir--instanceinstance_name[remote_options]
where:
data_dir is the data directory of the
cluster you are going to back up. To set up and use
lt_probackup, write access to this directory is required.
instance_name is the name of the
subdirectories that will store WAL and backup files for this
cluster.
remote_options
are optional parameters that need to be specified only if
data_dir is located
on a remote system.
lt_probackup creates the instance_name
subdirectories under the backups/ and wal/ directories of
the backup catalog. The
backups/ directory contains
the instance_namepg_probackup.conf configuration file that controls
lt_probackup settings for this backup instance. If you run this
command with the
remote_options, the specified
parameters will be added to pg_probackup.conf.
For details on how to fine-tune lt_probackup configuration, see the section called “Configuring lt_probackup”.
The user launching lt_probackup must have full access to
backup_dir directory and at least read-only
access to data_dir directory. If you
specify the path to the backup catalog in the
BACKUP_PATH environment variable, you can
omit the corresponding option when running lt_probackup
commands.
It is recommended to use the allow-group-access feature, so that backup can be done by any OS user in the same group as the cluster owner. In this case, the user should have read permissions for the cluster directory.
Although lt_probackup can be used by a superuser, it is
recommended to create a separate role with the minimum
permissions required for the chosen backup strategy. In these
configuration instructions, the backup role
is used as an example.
To perform a backup, the following
permissions for role backup are required
only in the database used for
connection to the LightDB server:
BEGIN; CREATE ROLE backup; GRANT USAGE ON SCHEMA pg_catalog TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.current_setting(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_is_in_recovery() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_start_backup(text, boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_stop_backup(boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_create_restore_point(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_switch_wal() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_last_wal_replay_lsn() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current_snapshot() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_snapshot_xmax(txid_snapshot) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_control_checkpoint() TO backup; COMMIT;
In the
lt_hba.conf
file, allow connection to the database instance on behalf of the
backup role.
Since lt_probackup needs to read cluster files directly,
lt_probackup must be started by (or connected to,
if used in the remote mode) the OS user that has read access to all files and
directories inside the data directory (LTDATA) you are going to
back up.
Depending on whether you plan to take standalone or archive backups, LightDB cluster configuration will differ, as specified in the sections below. To back up the database instance from a standby server, run lt_probackup in the remote mode, or create PTRACK backups, additional setup is required.
For details, see the sections Setting up STREAM Backups, Setting up continuous WAL archiving, Setting up Backup from Standby, Configuring the Remote Mode, Setting up Partial Restore, and Setting up PTRACK Backups.
To set up the cluster for STREAM backups, complete the following steps:
Grant the REPLICATION privilege to the backup role:
ALTER ROLE backup WITH REPLICATION;
In the
lt_hba.conf
file, allow replication on behalf of the
backup role.
Make sure the parameter max_wal_senders is set high enough to leave at least one session available for the backup process.
Set the parameter
wal_level
to be higher than minimal.
If you are planning to take PAGE backups in the STREAM mode or perform PITR with STREAM backups, you still have to configure WAL archiving, as explained in the section Setting up continuous WAL archiving.
Once these steps are complete, you can start taking FULL, PAGE, DELTA, and PTRACK backups in the STREAM WAL mode.
If you are planning to rely on
.pgpass
for authentication when running backup in STREAM mode,
then .pgpass must contain credentials for replication database,
used to establish connection via replication protocol. Example:
pghost:5432:replication:backup_user:my_strong_password
Making backups in PAGE backup mode, performing PITR, making backups with ARCHIVE WAL delivery mode and running incremental backup after timeline switch require continuous WAL archiving to be enabled. To set up continuous archiving in the cluster, complete the following steps:
Make sure the
wal_level
parameter is higher than minimal.
If you are configuring archiving on master,
archive_mode
must be set to on or
always. To perform archiving on standby,
set this parameter to always.
Set the archive_command parameter, as follows:
archive_command = '"install_dir/lt_probackup" archive-push -B "backup_dir" --instanceinstance_name--wal-file-name=%f [remote_options]'
where install_dir is the
installation directory of the lt_probackup
version you are going to use, backup_dir and
instance_name refer to the already
initialized backup catalog instance for this database instance,
and remote_options
only need to be specified to archive WAL on a remote host. For details about all
possible archive-push parameters, see the
section archive-push.
Once these steps are complete, you can start making backups in the ARCHIVE WAL mode, backups in the PAGE backup mode, as well as perform PITR.
You can view the current state of the WAL archive using the show command. For details, see the section called “Viewing WAL Archive Information”.
If you are planning to make PAGE backups and/or backups with
ARCHIVE WAL mode from a
standby server that generates a small amount of WAL traffic,
without long waiting for WAL segment to fill up, consider
setting the
archive_timeout
LightDB parameter on
master. The value of this parameter should be slightly
lower than the --archive-timeout setting (5 minutes by default),
so that there is enough time for the rotated
segment to be streamed to standby and sent to WAL archive before the
backup is aborted because of --archive-timeout.
Instead of using the archive-push
command provided by lt_probackup, you can use
any other tool to set up continuous archiving as long as it delivers WAL segments into
backup_dir/wal/instance_namegzip, and .gz suffix in filename is
mandatory.
Instead of configuring continuous archiving by setting the
archive_mode and archive_command
parameters, you can opt for using the
pg_receivewal
utility. In this case, pg_receivewal -D
option should point to
directorybackup_dir/wal/instance_name
For LightDB, lt_probackup can take backups from a standby server. This requires the following additional setup:
On the standby server, set the
hot_standby
parameter to on.
On the master server, set the
full_page_writes
parameter to on.
To perform standalone backups on standby, complete all steps in section Setting up STREAM Backups.
To perform archive backups on standby, complete all steps in section Setting up continuous WAL archiving.
Once these steps are complete, you can start taking FULL, PAGE, DELTA, or PTRACK backups with appropriate WAL delivery mode: ARCHIVE or STREAM, from the standby server.
Backup from the standby server has the following limitations:
If the standby is promoted to the master during backup, the backup fails.
All WAL records required for the backup must contain
sufficient full-page writes. This requires you to enable
full_page_writes on the master, and not
to use tools like pg_compresslog as
archive_command
to remove full-page writes from WAL files.
Logical verification of a database instance requires the following
additional setup. Role backup is used as an
example:
Install the amcheck in every database of the cluster:
CREATE EXTENSION amcheck;
Grant the following permissions to the backup
role in every database of the cluster:
GRANT SELECT ON TABLE pg_catalog.pg_am TO backup; GRANT SELECT ON TABLE pg_catalog.pg_class TO backup; GRANT SELECT ON TABLE pg_catalog.pg_database TO backup; GRANT SELECT ON TABLE pg_catalog.pg_namespace TO backup; GRANT SELECT ON TABLE pg_catalog.pg_extension TO backup; GRANT EXECUTE ON FUNCTION bt_index_check(regclass) TO backup; GRANT EXECUTE ON FUNCTION bt_index_check(regclass, bool) TO backup;
If you are planning to use partial restore, complete the following additional step:
Grant the read-only access to pg_catalog.pg_database to the
backup role only in the database
used for connection to
LightDB server:
GRANT SELECT ON TABLE pg_catalog.pg_database TO backup;
lt_probackup supports the remote mode that allows to perform backup, restore and WAL archiving operations remotely. In this mode, the backup catalog is stored on a local system, while LightDB instance to backup and/or to restore is located on a remote system. Currently the only supported remote protocol is SSH.
If you are going to use lt_probackup in remote mode via SSH, complete the following steps:
Install lt_probackup on both systems:
backup_host and
db_host.
For communication between the hosts set up the passwordless
SSH connection between backup user on
backup_host and
lightdb user on
db_host:
[backup@backup_host] ssh-copy-id lightdb@db_host
If you are going to rely on
continuous
WAL archiving, set up passwordless SSH
connection between lightdb user on
db_host and backup
user on backup_host:
[lightdb@db_host] ssh-copy-id backup@backup_host
where:
backup_host is the system with
backup catalog.
db_host is the system with LightDB
cluster.
backup is the OS user on
backup_host used to run lt_probackup.
lightdb is the OS user on
db_host used to start the LightDB
cluster. For LightDB a
more secure approach can be used thanks to
allow-group-access
feature.
lt_probackup in the remote mode via SSH works as follows:
Only the following commands can be launched in the remote mode: add-instance, backup, restore, archive-push, archive-get.
Operating in remote mode requires lt_probackup binary to be installed on both local and remote systems. The versions of local and remote binary must be the same.
When started in the remote mode, the main lt_probackup process
on the local system connects to the remote system via SSH and
launches one or more agent processes on the remote system, which are called
remote agents. The number of remote agents
is equal to the -j/--threads setting.
The main lt_probackup process uses remote agents to access remote files and transfer data between local and remote systems.
Remote agents try to minimize the network traffic and the number of round-trips between hosts.
The main process is usually started on
backup_host and connects to
db_host, but in case of
archive-push and
archive-get commands the main process
is started on db_host and connects to
backup_host.
Once data transfer is complete, remote agents are terminated and SSH connections are closed.
If an error condition is encountered by a remote agent, then all agents are terminated and error details are reported by the main lt_probackup process, which exits with an error.
Compression is always done on
db_host, while decompression is always done on
backup_host.
You can impose additional restrictions on SSH settings to protect the system in the event of account compromise.
The PTRACK backup mode can be used for LightDB. Links to PTRACK patches can be found here.
PTRACK Will be used directly in feature.
If you are going to use PTRACK backups, complete the following
additional steps. The role that will perform PTRACK backups
(the backup role in the examples below) must have
access to all the databases of the cluster.
For LightDB :
Create PTRACK extension:
CREATE EXTENSION ptrack;
To enable tracking page updates, set ptrack.map_size
parameter to a positive integer and restart the server.
For optimal performance, it is recommended to set
ptrack.map_size to
N / 1024N is the size of the
LightDB cluster, in MB. If you set this
parameter to a lower value, PTRACK is more likely to map several blocks
together, which leads to false-positive results when tracking changed
blocks and increases the incremental backup size as unchanged blocks
can also be copied into the incremental backup.
Setting ptrack.map_size to a higher value does not
affect PTRACK operation, but it is not recommended to set this parameter
to a value higher than 1024.
If you change the ptrack.map_size parameter value,
the previously created PTRACK map file is cleared,
and tracking newly changed blocks starts from scratch. Thus, you have
to retake a full backup before taking incremental PTRACK backups after
changing ptrack.map_size.
To create a backup, run the following command:
lt_probackup backup -Bbackup_dir--instanceinstance_name-bbackup_mode
Where backup_mode can take one of the
following values:
FULL — creates a full backup that contains all the data files of the cluster to be restored.
DELTA — reads all data files in the data directory and creates an incremental backup for pages that have changed since the previous backup.
PAGE — creates an incremental backup based on the WAL files that have been generated since the previous full or incremental backup was taken. Only changed blocks are read from data files.
PTRACK — creates an incremental backup tracking page changes on the fly.
When restoring a cluster from an incremental backup, lt_probackup relies on the parent full backup and all the incremental backups between them, which is called “the backup chain”. You must create at least one full backup before taking incremental ones.
ARCHIVE is the default WAL delivery mode.
For example, to make a FULL backup in ARCHIVE mode, run:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL
ARCHIVE backups rely on continuous archiving to get WAL segments required to restore the cluster to a consistent state at the time the backup was taken.
When a backup is taken, lt_probackup
ensures that WAL files containing WAL records between Start
LSN and Stop LSN actually exist in
backup_dir/wal/instance_nameStart LSN and Stop LSN can be parsed. This precaution
eliminates the risk of silent WAL corruption.
STREAM is the optional WAL delivery mode.
For example, to make a FULL backup in the STREAM mode, add the
--stream flag to the command from the
previous example:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --stream --temp-slot
The optional --temp-slot flag ensures that
the required segments remain available if the WAL is rotated
before the backup is complete.
Unlike backups in ARCHIVE mode, STREAM backups include all the WAL segments required to restore the cluster to a consistent state at the time the backup was taken.
During backup lt_probackup
streams WAL files containing WAL records between Start LSN and
Stop LSN to
backup_dir/backups/instance_name/backup_id/database/lt_walStart LSN and
Stop LSN can be parsed.
Even if you are using continuous archiving, STREAM backups can still be useful in the following cases:
STREAM backups can be restored on the server that has no file access to WAL archive.
STREAM backups enable you to restore the cluster state at the point in time for which WAL files in archive are no longer available.
Backup in STREAM mode can be taken from a standby of a server that generates small amount of WAL traffic, without long waiting for WAL segment to fill up.
If data checksums are enabled in the database instance, lt_probackup uses this information to check correctness of data files during backup. While reading each page, lt_probackup checks whether the calculated checksum coincides with the checksum stored in the page header. This guarantees that the LightDB instance and the backup itself have no corrupt pages. Note that lt_probackup reads database files directly from the filesystem, so under heavy write load during backup it can show false-positive checksum mismatches because of partial writes. If a page checksum mismatch occurs, the page is re-read and checksum comparison is repeated.
A page is considered corrupt if checksum comparison has failed more than 100 times. In this case, the backup is aborted.
Even if data checksums are not enabled, lt_probackup always performs sanity checks for page headers.
To back up a directory located outside of the data directory,
use the optional --external-dirs parameter
that specifies the path to this directory. If you would like
to add more than one external directory, you can provide several paths
separated by colons on Linux systems or semicolons on Windows systems.
For example, to include /etc/dir1 and
/etc/dir2 directories into the full
backup of your instance_name instance
that will be stored under the backup_dir
directory on Linux, run:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --external-dirs=/etc/dir1:/etc/dir2
lt_probackup recursively copies the contents of each external directory into a separate subdirectory in the backup catalog. Since external directories included into different backups do not have to be the same, when you are restoring the cluster from an incremental backup, only those directories that belong to this particular backup will be restored. Any external directories stored in the previous backups will be ignored.
To include the same directories into each backup of your
instance, you can specify them in the pg_probackup.conf
configuration file using the
set-config command with the
--external-dirs option.
To verify that LightDB database instance is not corrupt, run the following command:
lt_probackup checkdb [-Bbackup_dir[--instanceinstance_name]] [-Ddata_dir] [connection_options]
This command performs physical verification of all data files
located in the specified data directory by running page header
sanity checks, as well as block-level checksum verification if checksums are enabled.
If a corrupt page is detected, checkdb
continues cluster verification until all pages in the cluster
are validated.
By default, similar page validation
is performed automatically while a backup is taken by
lt_probackup. The checkdb
command enables you to perform such page validation
on demand, without taking any backup copies, even if the cluster
is not backed up using lt_probackup at all.
To perform cluster verification, lt_probackup
needs to connect to the cluster to be verified. In general, it is
enough to specify the backup instance of this cluster for
lt_probackup to determine the required
connection options. However, if -B and
--instance options are omitted, you have to provide
connection options and
data_dir via environment
variables or command-line options.
Physical verification cannot detect logical inconsistencies, missing or nullified blocks and entire files, or similar anomalies. Extensions amcheck provide a partial solution to these problems.
If you would like, in addition to physical verification, to
verify all indexes in all databases using these extensions, you
can specify the --amcheck flag when running
the checkdb command:
lt_probackup checkdb -Ddata_dir--amcheck [connection_options]
You can skip physical verification by specifying the
--skip-block-validation flag. In this case,
you can omit backup_dir and
data_dir options, only
connection options are
mandatory:
lt_probackup checkdb --amcheck --skip-block-validation [connection_options]
Logical verification can be done more thoroughly with the
--heapallindexed flag by checking that all heap
tuples that should be indexed are actually indexed, but at the
higher cost of CPU, memory, and I/O consumption.
lt_probackup calculates checksums for each file in a backup during the backup process. The process of checking checksums of backup data files is called the backup validation. By default, validation is run immediately after the backup is taken and right before the restore, to detect possible backup corruption.
If you would like to skip backup validation, you can specify the
--no-validate flag when running
backup and
restore commands.
To ensure that all the required backup files are present and can be used to restore the database instance, you can run the validate command with the exact recovery target options you are going to use for recovery.
For example, to check that you can restore the database instance from a backup copy up to transaction ID 4242, run this command:
lt_probackup validate -Bbackup_dir--instanceinstance_name--recovery-target-xid=4242
If validation completes successfully, lt_probackup displays the corresponding message. If validation fails, you will receive an error message with the exact time, transaction ID, and LSN up to which the recovery is possible.
If you specify backup_id via
-i/--backup-id option, then only the backup copy
with specified backup ID will be validated. If
backup_id is specified with
recovery target
options, the validate command will check whether it is possible
to restore the specified backup to the specified
recovery target.
For example, to check that you can restore the database instance
from a backup copy with the PT8XFX backup ID up to the
specified timestamp, run this command:
lt_probackup validate -Bbackup_dir--instanceinstance_name-i PT8XFX --recovery-target-time="2017-05-18 14:18:11+03"
If you specify the backup_id of an incremental backup,
all its parents starting from FULL backup will be
validated.
If you omit all the parameters, all backups are validated.
To restore the database instance from a backup, run the restore command with at least the following options:
lt_probackup restore -Bbackup_dir--instanceinstance_name-ibackup_id
where:
backup_dir is the backup catalog that
stores all backup files and meta information.
instance_name is the backup instance
for the cluster to be restored.
backup_id specifies the backup to
restore the cluster from. If you omit this option,
lt_probackup uses the latest valid backup available for the
specified instance. If you specify an incremental backup to
restore, lt_probackup automatically restores the underlying
full backup and then sequentially applies all the necessary
increments.
Once the restore command is complete, start
the database service.
If you restore ARCHIVE backups,
perform PITR,
or specify the --restore-as-replica flag with the
restore command to set up a standby server,
lt_probackup creates a recovery configuration
file once all data files are copied into the target directory. This file
includes the minimal settings required for recovery, except for the password in the
primary_conninfo
parameter; you have to add the password manually or use
the --primary-conninfo option, if required.
For LightDB,
lt_probackup writes these settings into
the probackup_recovery.conf file and then includes
it into lightdb.auto.conf.
If you are restoring a STREAM backup, the restore is complete
at once, with the cluster returned to a self-consistent state at
the point when the backup was taken. For ARCHIVE backups,
LightDB replays all available archived WAL
segments, so the cluster is restored to the latest state possible
within the current timeline. You can change this behavior by using the
recovery target
options with the restore command,
as explained in the section called “Performing Point-in-Time (PITR) Recovery”.
If the cluster to restore contains tablespaces, lt_probackup
restores them to their original location by default. To restore
tablespaces to a different location, use the
--tablespace-mapping/-T option. Otherwise,
restoring the cluster on the same host will fail if tablespaces
are in use, because the backup would have to be written to the
same directories.
When using the --tablespace-mapping/-T
option, you must provide absolute paths to the old and new
tablespace directories. If a path happens to contain an equals
sign (=), escape it with a backslash. This option can be
specified multiple times for multiple tablespaces. For example:
lt_probackup restore -Bbackup_dir--instanceinstance_name-Ddata_dir-j 4 -ibackup_id-T tablespace1_dir=tablespace1_newdir-T tablespace2_dir=tablespace2_newdir
To restore the cluster on a remote host, follow the instructions in the section called “Using lt_probackup in the Remote Mode”.
By default, the restore
command validates the specified backup before restoring the
cluster. If you run regular backup validations and would like
to save time when restoring the cluster, you can specify the
--no-validate flag to skip validation and
speed up the recovery.
The speed of restore from backup can be significantly improved by replacing only invalid and changed pages in already existing LightDB data directory using incremental restore options with the restore command.
To restore the database instance from a backup in incremental mode, run the restore command with the following options:
lt_probackup restore -Bbackup_dir--instanceinstance_name-Ddata_dir-Iincremental_mode
Where incremental_mode can take one of the
following values:
CHECKSUM — read all data files in the data directory, validate header and checksum in every page and replace only invalid pages and those with checksum and LSN not matching with corresponding page in backup. This is the simplest, the most fool-proof incremental mode. Recommended to use by default.
LSN — read the lt_control in the
data directory to obtain redo LSN and redo TLI, which allows
to determine a point in history(shiftpoint), where data directory
state shifted from target backup chain history. If shiftpoint is not within
reach of backup chain history, then restore is aborted.
If shiftpoint is within reach of backup chain history, then read
all data files in the data directory, validate header and checksum in
every page and replace only invalid pages and those with LSN greater
than shiftpoint.
This mode offers a greater speed up compared to CHECKSUM, but rely
on two conditions to be met. First,
data checksums parameter must be enabled in data directory (to avoid corruption
due to hint bits). This condition will be checked at the start of
incremental restore and the operation will be aborted if checksums are disabled.
Second, the lt_control file must be
synched with state of data directory. This condition cannot checked
at the start of restore, so it is a user responsibility to ensure
that lt_control contain valid information.
Therefore it is not recommended to use LSN mode in any situation,
where lt_control cannot be trusted or has been tampered with:
after pg_resetxlog execution,
after restore from backup without recovery been run, etc.
NONE — regular restore without any incremental optimizations.
Regardless of chosen incremental mode, lt_probackup will check, that postmaster
in given destination directory is not running and system-identifier is
the same as in the backup.
Suppose you want to return an old master as replica after switchover using incremental restore in LSN mode:
=============================================================================================================================================
Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zratio Start LSN Stop LSN Status
=============================================================================================================================================
node 12 QBRNBP 2020-06-11 17:40:58+03 DELTA ARCHIVE 16/15 40s 194MB 16MB 8.26 15/2C000028 15/2D000128 OK
node 12 QBRIDX 2020-06-11 15:51:42+03 PAGE ARCHIVE 15/15 11s 18MB 16MB 5.10 14/DC000028 14/DD0000B8 OK
node 12 QBRIAJ 2020-06-11 15:51:08+03 PAGE ARCHIVE 15/15 20s 141MB 96MB 6.22 14/D4BABFE0 14/DA9871D0 OK
node 12 QBRHT8 2020-06-11 15:45:56+03 FULL ARCHIVE 15/0 2m:11s 1371MB 416MB 10.93 14/9D000028 14/B782E9A0 OK
lt_probackup restore -B /backup --instance node -R -I lsn
INFO: Running incremental restore into nonempty directory: "/var/lib/lightdb-x/12/data"
INFO: Destination directory redo point 15/2E000028 on tli 16 is within reach of backup QBRIDX with Stop LSN 14/DD0000B8 on tli 15
INFO: shift LSN: 14/DD0000B8
INFO: Restoring the database from backup at 2020-06-11 17:40:58+03
INFO: Extracting the content of destination directory for incremental restore
INFO: Destination directory content extracted, time elapsed: 1s
INFO: Removing redundant files in destination directory
INFO: Redundant files are removed, time elapsed: 1s
INFO: Start restoring backup files. LTDATA size: 15GB
INFO: Backup files are restored. Transfered bytes: 1693MB, time elapsed: 43s
INFO: Restore incremental ratio (less is better): 11% (1693MB/15GB)
INFO: Restore of backup QBRNBP completed.
Incremental restore is possible only for backups with
program_version equal or greater than 2.4.0.
If you have enabled partial restore before taking backups, you can restore only some of the databases using partial restore options with the restore commands.
To restore the specified databases only, run the restore command with the following options:
lt_probackup restore -Bbackup_dir--instanceinstance_name--db-include=database_name
The --db-include option can be specified
multiple times. For example, to restore only databases
db1 and db2, run the
following command:
lt_probackup restore -Bbackup_dir--instanceinstance_name--db-include=db1 --db-include=db2
To exclude one or more databases from restore, use
the --db-exclude option:
lt_probackup restore -Bbackup_dir--instanceinstance_name--db-exclude=database_name
The --db-exclude option can be specified
multiple times. For example, to exclude the databases
db1 and db2 from
restore, run the following command:
lt_probackup restore -Bbackup_dir--instanceinstance_name--db-exclude=db1 --db-exclude=db2
Partial restore relies on lax behavior of LightDB recovery
process toward truncated files. For recovery to work properly, files of excluded databases
are restored as files of zero size. After the LightDB cluster is successfully started,
you must drop the excluded databases using
DROP DATABASE command.
To decouple a single cluster containing multiple databases into separate clusters with minimal downtime,
you can do partial restore of the cluster as a standby using the --restore-as-replica option
for specific databases.
The template0 and
template1 databases are always restored.
If you have enabled continuous WAL archiving before taking backups, you can restore the cluster to its state at an arbitrary point in time (recovery target) using recovery target options with the restore command.
You can use both STREAM and ARCHIVE backups for point in time
recovery as long as the WAL archive is available at least starting
from the time the backup was taken.
If -i/--backup-id option is omitted,
lt_probackup automatically chooses the backup that is the
closest to the specified recovery target and starts the restore
process, otherwise lt_probackup will try to restore
the specified backup to the specified recovery target.
To restore the cluster state at the exact time, specify the
--recovery-target-time option, in the
timestamp format. For example:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target-time="2017-05-18 14:18:11+03"
To restore the cluster state up to a specific transaction
ID, use the --recovery-target-xid option:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target-xid=687
To restore the cluster state up to the specific LSN, use
--recovery-target-lsn option:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target-lsn=16/B374D848
To restore the cluster state up to the specific named restore
point, use --recovery-target-name option:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target-name="before_app_upgrade"
To restore the backup to the latest state available in
the WAL archive, use --recovery-target option
with latest value:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target="latest"
To restore the cluster to the earliest point of consistency,
use --recovery-target option with the
immediate value:
lt_probackup restore -Bbackup_dir--instanceinstance_name--recovery-target='immediate'
lt_probackup supports the remote mode that allows to perform
backup and restore
operations remotely via SSH. In this mode, the backup catalog is
stored on a local system, while LightDB instance to be backed
up is located on a remote system. You must have lt_probackup
installed on both systems.
lt_probackup relies on passwordless SSH connection for communication between the hosts.
The typical workflow is as follows:
On your backup host, configure lt_probackup as explained in the section Installation and Setup. For the add-instance and set-config commands, make sure to specify remote options that point to the database host with the LightDB instance.
If you would like to take remote backups in PAGE mode, or rely on ARCHIVE WAL delivery mode, or use PITR, configure continuous WAL archiving from the database host to the backup host as explained in the section Setting up continuous WAL archiving. For the archive-push and archive-get commands, you must specify the remote options that point to the backup host with the backup catalog.
Run backup or restore commands with remote options on the backup host. lt_probackup connects to the remote system via SSH and creates a backup locally or restores the previously taken backup on the remote system, respectively.
For example, to create an archive full backup of a
LightDB cluster located on
a remote system with host address 192.168.0.2
on behalf of the lightdb user via SSH connection
through port 2302, run:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --remote-user=lightdb --remote-host=192.168.0.2 --remote-port=2302
To restore the latest available backup on a remote system with host address
192.168.0.2 on behalf of the lightdb
user via SSH connection through port 2302, run:
lt_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=lightdb--remote-host=192.168.0.2 --remote-port=2302
Restoring an ARCHIVE backup or performing PITR in the remote mode
require additional information: destination address, port and
username for establishing an SSH connection
from the host with database
to the host with the backup
catalog. This information will be used by the
restore_command to copy WAL segments
from the archive to the LightDB lt_wal directory.
To solve this problem, you can use Remote WAL Archive Options.
For example, to restore latest backup on remote system using
remote mode through SSH connection to user
lightdb on host with address
192.168.0.2 via port 2302
and user backup on backup catalog host with
address 192.168.0.3 via port
2303, run:
lt_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=lightdb--remote-host=192.168.0.2 --remote-port=2302 --archive-host=192.168.0.3 --archive-port=2303 --archive-user=backup
Provided arguments will be used to construct the restore_command:
restore_command = '"install_dir/lt_probackup" archive-get -B "backup_dir" --instanceinstance_name--wal-file-path=%p --wal-file-name=%f --remote-host=192.168.0.3 --remote-port=2303 --remote-user=backup'
Alternatively, you can use the --restore-command
option to provide the entire restore_command:
lt_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=lightdb --remote-host=192.168.0.2 --remote-port=2302 --restore-command='"install_dir/lt_probackup" archive-get -B "backup_dir" --instanceinstance_name--wal-file-path=%p --wal-file-name=%f --remote-host=192.168.0.3 --remote-port=2303 --remote-user=backup'
The remote mode is currently unavailable for Windows systems.
backup, restore, merge, delete, checkdb and validate processes can be executed on several parallel threads. This can significantly speed up lt_probackup operation given enough resources (CPU cores, disk, and network bandwidth).
Parallel execution is controlled by the
-j/--threads command-line option. For
example, to create a backup using four parallel threads, run:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL -j 4
Parallel restore applies only to copying data from the backup catalog to the data directory of the cluster. When LightDB server is started, WAL records need to be replayed, and this cannot be done in parallel.
Once the backup catalog is initialized and a new backup instance
is added, you can use the pg_probackup.conf configuration file
located in the
backup_dir/backups/instance_name
For example, backup and
checkdb commands use a regular
LightDB connection. To avoid specifying
connection options
each time on the command line, you can set them in the
pg_probackup.conf configuration file using the
set-config command.
It is not recommended
to edit pg_probackup.conf manually.
Initially, pg_probackup.conf contains the following settings:
LTDATA — the path to the data directory of the cluster to
back up.
system-identifier — the unique identifier of the LightDB
instance.
Additionally, you can define
remote,
retention,
logging, and
compression settings
using the set-config command:
lt_probackup set-config -Bbackup_dir--instanceinstance_name[--external-dirs=external_directory_path] [remote_options] [connection_options] [retention_options] [logging_options]
To view the current settings, run the following command:
lt_probackup show-config -Bbackup_dir--instanceinstance_name
You can override the settings defined in pg_probackup.conf when
running lt_probackup commands
via the corresponding environment variables and/or command line
options.
If you define connection settings in the pg_probackup.conf
configuration file, you can omit connection options in all the
subsequent lt_probackup commands. However, if the corresponding
environment variables are set, they get higher priority. The
options provided on the command line overwrite both environment
variables and configuration file settings.
If nothing is given, the default values are taken. By default
lt_probackup tries to use local connection via Unix domain
socket (localhost on Windows) and tries to get the database name
and the user name from the LTUSER environment variable or the
current OS user name.
With lt_probackup, you can manage backups from the command line:
To view the list of existing backups for every instance, run the command:
lt_probackup show -B backup_dir
lt_probackup displays the list of all the available backups. For example:
BACKUP INSTANCE 'node' ====================================================================================================================================== Instance Version ID Recovery time Mode WAL Mode TLI Time Data WAL Zratio Start LSN Stop LSN Status ====================================================================================================================================== node 10 PYSUE8 2019-10-03 15:51:48+03 FULL ARCHIVE 1/0 16s 9047kB 16MB 4.31 0/12000028 0/12000160 OK node 10 P7XDQV 2018-04-29 05:32:59+03 DELTA STREAM 1/1 11s 19MB 16MB 1.00 0/15000060 0/15000198 OK node 10 P7XDJA 2018-04-29 05:28:36+03 PTRACK STREAM 1/1 21s 32MB 32MB 1.00 0/13000028 0/13000198 OK node 10 P7XDHU 2018-04-29 05:27:59+03 PAGE STREAM 1/1 15s 33MB 16MB 1.00 0/11000028 0/110001D0 OK node 10 P7XDHB 2018-04-29 05:27:15+03 FULL STREAM 1/0 11s 39MB 16MB 1.00 0/F000028 0/F000198 OK
For each backup, the following information is provided:
Instance — the instance name.
Version — LightDB major version.
ID — the backup identifier.
Recovery time — the earliest moment for which you can
restore the state of the database instance.
Mode — the method used to take this backup. Possible
values: FULL, PAGE, DELTA, PTRACK.
WAL Mode — WAL delivery mode. Possible values: STREAM
and ARCHIVE.
TLI — timeline identifiers of the current backup and its
parent.
Time — the time it took to perform the backup.
Data — the size of the data files in this backup. This
value does not include the size of WAL files. For
STREAM backups, the total size of the backup can be calculated
as Data + WAL.
WAL — the uncompressed size of WAL files
that need to be applied during recovery for the backup to reach a consistent state.
Zratio — compression ratio calculated as
“uncompressed-bytes” / “data-bytes”.
Start LSN — WAL log sequence number corresponding to the
start of the backup process. REDO point for LightDB
recovery process to start from.
Stop LSN — WAL log sequence number corresponding to the
end of the backup process. Consistency point for
LightDB recovery process.
Status — backup status. Possible values:
OK — the backup is complete and valid.
DONE — the backup is complete, but was not validated.
RUNNING — the backup is in progress.
MERGING — the backup is being merged.
MERGED — the backup data files were
successfully merged, but its metadata is in the process
of being updated. Only full backups can have this status.
DELETING — the backup files are being deleted.
CORRUPT — some of the backup files are corrupt.
ERROR — the backup was aborted because of an
unexpected error.
ORPHAN — the backup is invalid because one of its
parent backups is corrupt or missing.
You can restore the cluster from the backup only if the backup
status is OK or DONE.
To get more detailed information about the backup, run the
show command with the backup ID:
lt_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
The sample output is as follows:
#Configuration backup-mode = FULL stream = false compress-alg = zlib compress-level = 1 from-replica = false #Compatibility block-size = 8192 wal-block-size = 8192 checksum-version = 1 program-version = 2.1.3 server-version = 10 #Result backup info timelineid = 1 start-lsn = 0/04000028 stop-lsn = 0/040000f8 start-time = '2017-05-16 12:57:29' end-time = '2017-05-16 12:57:31' recovery-xid = 597 recovery-time = '2017-05-16 12:57:31' expire-time = '2020-05-16 12:57:31' data-bytes = 22288792 wal-bytes = 16777216 uncompressed-bytes = 39961833 pgdata-bytes = 39859393 status = OK parent-backup-id = 'PT8XFX' primary_conninfo = 'user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any'
Detailed output has additional attributes:
compress-alg — compression algorithm used during backup. Possible values:
zlib, pglz, none.
compress-level — compression level used during backup.
from-replica — was this backup taken on standby? Possible values:
1, 0.
block-size — the block_size
setting of LightDB cluster at the backup start.
checksum-version — are
data
block checksums enabled in the backed up LightDB cluster? Possible values: 1, 0.
program-version — full version of lt_probackup binary used to create the backup.
start-time — the backup start time.
end-time — the backup end time.
expire-time — the point in time
when a pinned backup can be removed in accordance with retention
policy. This attribute is only available for pinned backups.
uncompressed-bytes — the size of data files before adding page headers and applying
compression. You can evaluate the effectiveness of compression
by comparing uncompressed-bytes to data-bytes if
compression if used.
pgdata-bytes — the size of LightDB
cluster data files at the time of backup. You can evaluate the
effectiveness of an incremental backup by comparing
pgdata-bytes to uncompressed-bytes.
recovery-xid — transaction ID at the backup end time.
parent-backup-id — ID of the parent backup. Available only
for incremental backups.
primary_conninfo — libpq connection parameters
used to connect to the LightDB cluster to take this backup. The
password is not included.
note — text note attached to backup.
content-crc — CRC32 checksum of backup_content.control file.
It is used to detect corruption of backup metainformation.
You can also get the detailed information about the backup in the JSON format:
lt_probackup show -Bbackup_dir--instanceinstance_name--format=json -i backup_id
The sample output is as follows:
[
{
"instance": "node",
"backups": [
{
"id": "PT91HZ",
"parent-backup-id": "PT8XFX",
"backup-mode": "DELTA",
"wal": "ARCHIVE",
"compress-alg": "zlib",
"compress-level": 1,
"from-replica": false,
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.3",
"server-version": "10",
"current-tli": 16,
"parent-tli": 2,
"start-lsn": "0/8000028",
"stop-lsn": "0/8000160",
"start-time": "2019-06-17 18:25:11+03",
"end-time": "2019-06-17 18:25:16+03",
"recovery-xid": 0,
"recovery-time": "2019-06-17 18:25:15+03",
"data-bytes": 106733,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
To view the information about WAL archive for every instance, run the command:
lt_probackup show -Bbackup_dir[--instanceinstance_name] --archive
lt_probackup displays the list of all the available WAL files grouped by timelines. For example:
ARCHIVE INSTANCE 'node' =================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zratio N backups Status =================================================================================================================================== 5 1 0/B000000 00000005000000000000000B 00000005000000000000000C 2 685kB 48.00 0 OK 4 3 0/18000000 000000040000000000000018 00000004000000000000001A 3 648kB 77.00 0 OK 3 2 0/15000000 000000030000000000000015 000000030000000000000017 3 648kB 77.00 0 OK 2 1 0/B000108 00000002000000000000000B 000000020000000000000015 5 892kB 94.00 1 DEGRADED 1 0 0/0 000000010000000000000001 00000001000000000000000A 10 8774kB 19.00 1 OK
For each timeline, the following information is provided:
TLI — timeline identifier.
Parent TLI — identifier of the timeline from which this timeline branched off.
Switchpoint — LSN of the moment when the timeline branched
off from its parent timeline.
Min Segno — the first WAL segment
belonging to the timeline.
Max Segno — the last WAL segment
belonging to the timeline.
N segments — number of WAL segments belonging to the
timeline.
Size — the size that files take on disk.
Zratio — compression ratio calculated as N segments *
wal_segment_size * wal_block_size / Size.
N backups — number of backups belonging to the timeline.
To get the details about backups, use the JSON format.
Status — status of the WAL archive for this timeline. Possible
values:
OK — all WAL segments between Min Segno
and Max Segno are present.
DEGRADED — some WAL segments between Min Segno
and Max Segno are missing. To find out which files are lost,
view this report in the JSON format.
To get more detailed information about the WAL archive in the JSON format, run the command:
lt_probackup show -Bbackup_dir[--instanceinstance_name] --archive --format=json
The sample output is as follows:
[
{
"instance": "replica",
"timelines": [
{
"tli": 5,
"parent-tli": 1,
"switchpoint": "0/B000000",
"min-segno": "00000005000000000000000B",
"max-segno": "00000005000000000000000C",
"n-segments": 2,
"size": 685320,
"zratio": 48.00,
"closest-backup-id": "PXS92O",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 4,
"parent-tli": 3,
"switchpoint": "0/18000000",
"min-segno": "000000040000000000000018",
"max-segno": "00000004000000000000001A",
"n-segments": 3,
"size": 648625,
"zratio": 77.00,
"closest-backup-id": "PXS9CE",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 3,
"parent-tli": 2,
"switchpoint": "0/15000000",
"min-segno": "000000030000000000000015",
"max-segno": "000000030000000000000017",
"n-segments": 3,
"size": 648911,
"zratio": 77.00,
"closest-backup-id": "PXS9CE",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 2,
"parent-tli": 1,
"switchpoint": "0/B000108",
"min-segno": "00000002000000000000000B",
"max-segno": "000000020000000000000015",
"n-segments": 5,
"size": 892173,
"zratio": 94.00,
"closest-backup-id": "PXS92O",
"status": "DEGRADED",
"lost-segments": [
{
"begin-segno": "00000002000000000000000D",
"end-segno": "00000002000000000000000E"
},
{
"begin-segno": "000000020000000000000010",
"end-segno": "000000020000000000000012"
}
],
"backups": [
{
"id": "PXS9CE",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 2,
"parent-tli": 0,
"start-lsn": "0/C000028",
"stop-lsn": "0/C000160",
"start-time": "2019-09-13 21:43:26+03",
"end-time": "2019-09-13 21:43:30+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:43:29+03",
"data-bytes": 104674852,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
},
{
"tli": 1,
"parent-tli": 0,
"switchpoint": "0/0",
"min-segno": "000000010000000000000001",
"max-segno": "00000001000000000000000A",
"n-segments": 10,
"size": 8774805,
"zratio": 19.00,
"closest-backup-id": "",
"status": "OK",
"lost-segments": [],
"backups": [
{
"id": "PXS92O",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "true",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 0,
"start-lsn": "0/4000028",
"stop-lsn": "0/6000028",
"start-time": "2019-09-13 21:37:36+03",
"end-time": "2019-09-13 21:38:45+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:30+03",
"data-bytes": 25987319,
"wal-bytes": 50331648,
"primary_conninfo": "user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
},
{
"instance": "master",
"timelines": [
{
"tli": 1,
"parent-tli": 0,
"switchpoint": "0/0",
"min-segno": "000000010000000000000001",
"max-segno": "00000001000000000000000B",
"n-segments": 11,
"size": 8860892,
"zratio": 20.00,
"status": "OK",
"lost-segments": [],
"backups": [
{
"id": "PXS92H",
"parent-backup-id": "PXS92C",
"backup-mode": "PAGE",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 1,
"start-lsn": "0/4000028",
"stop-lsn": "0/50000B8",
"start-time": "2019-09-13 21:37:29+03",
"end-time": "2019-09-13 21:37:31+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:30+03",
"data-bytes": 1328461,
"wal-bytes": 33554432,
"primary_conninfo": "user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
},
{
"id": "PXS92C",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 0,
"start-lsn": "0/2000028",
"stop-lsn": "0/2000160",
"start-time": "2019-09-13 21:37:24+03",
"end-time": "2019-09-13 21:37:29+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:28+03",
"data-bytes": 24871902,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/lightdb-x/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
}
]
Most fields are consistent with the plain format, with some exceptions:
The size is in bytes.
The closest-backup-id attribute
contains the ID of the most recent valid backup that belongs to
one of the previous timelines. You can use this backup to perform
point-in-time recovery to this timeline. If
such a backup does not exist, this string is empty.
The lost-segments array provides with
information about intervals of missing segments in DEGRADED timelines. In OK
timelines, the lost-segments array is empty.
The backups array lists all backups
belonging to the timeline. If the timeline has no backups, this array is empty.
With lt_probackup, you can configure retention policy to remove redundant backups, clean up unneeded WAL files, as well as pin specific backups to ensure they are kept for the specified time, as explained in the sections below. All these actions can be combined together in any way.
By default, all backup copies created with lt_probackup are stored in the specified backup catalog. To save disk space, you can configure retention policy to remove redundant backup copies.
To configure retention policy, set one or more of the
following variables in the pg_probackup.conf file via
set-config:
--retention-redundancy=redundancy
Specifies the number of full backup copies to keep in the backup catalog.
--retention-window=window
Defines the earliest point in time for which lt_probackup can
complete the recovery. This option is set in
the number of days from the
current moment. For example, if
retention-window=7, lt_probackup must
keep at least one backup copy that is older than seven days, with
all the corresponding WAL files, and all the backups that follow.
If both --retention-redundancy and
--retention-window options are set, both these
conditions have to be taken into account when purging the backup
catalog. For example, if you set --retention-redundancy=2
and --retention-window=7,
lt_probackup has to keep two full backup
copies, as well as all the backups required to ensure recoverability
for the last seven days:
lt_probackup set-config -Bbackup_dir--instanceinstance_name--retention-redundancy=2 --retention-window=7
To clean up the backup catalog in accordance with retention policy, you have to run the delete command with retention flags, as shown below, or use the backup command with these flags to process the outdated backup copies right when the new backup is created.
For example, to remove all backup copies that no longer satisfy the
defined retention policy, run the following command with the
--delete-expired flag:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired
If you would like to also remove the WAL files that are no
longer required for any of the backups, you should also specify the
--delete-wal flag:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --delete-wal
You can also set or override the current retention policy by
specifying --retention-redundancy and
--retention-window options directly when
running delete or backup
commands:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --retention-window=7 --retention-redundancy=2
Since incremental backups require that their parent full
backup and all the preceding incremental backups are
available, if any of such backups expire, they still cannot be
removed while at least one incremental backup in this chain
satisfies the retention policy. To avoid keeping expired
backups that are still required to restore an active
incremental one, you can merge them with this backup using the
--merge-expired flag when running
backup or
delete commands.
Suppose you have backed up the node
instance in the backup_dir directory,
with the --retention-window option set
to 7, and you have the following backups
available on April 10, 2019:
BACKUP INSTANCE 'node' =================================================================================================================================== Instance Version ID Recovery time Mode WAL TLI Time Data WAL Zratio Start LSN Stop LSN Status =================================================================================================================================== node 10 P7XDHR 2019-04-10 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB 1.0 0/18000059 0/18000197 OK node 10 P7XDQV 2019-04-08 05:32:59+03 PAGE STREAM 1/0 11s 19MB 16MB 1.0 0/15000060 0/15000198 OK node 10 P7XDJA 2019-04-03 05:28:36+03 DELTA STREAM 1/0 21s 32MB 16MB 1.0 0/13000028 0/13000198 OK -------------------------------------------------------retention window-------------------------------------------------------- node 10 P7XDHU 2019-04-02 05:27:59+03 PAGE STREAM 1/0 31s 33MB 16MB 1.0 0/11000028 0/110001D0 OK node 10 P7XDHB 2019-04-01 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB 1.0 0/F000028 0/F000198 OK node 10 P7XDFT 2019-03-29 05:26:25+03 FULL STREAM 1/0 11s 200MB 16MB 1.0 0/D000028 0/D000198 OK
Even though P7XDHB and P7XDHU backups are outside the
retention window, they cannot be removed as it invalidates the
succeeding incremental backups P7XDJA and P7XDQV that are
still required, so, if you run the
delete command with the
--delete-expired flag, only the P7XDFT full
backup will be removed.
With the --merge-expired option, the P7XDJA
backup is merged with the underlying P7XDHU and P7XDHB backups
and becomes a full one, so there is no need to keep these
expired backups anymore:
lt_probackup delete -Bbackup_dir--instancenode--delete-expired --merge-expired lt_probackup show -Bbackup_dir
BACKUP INSTANCE 'node' ================================================================================================================================== Instance Version ID Recovery time Mode WAL TLI Time Data WAL Zratio Start LSN Stop LSN Status ================================================================================================================================== node 10 P7XDHR 2019-04-10 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB 1.0 0/18000059 0/18000197 OK node 10 P7XDQV 2019-04-08 05:32:59+03 PAGE STREAM 1/0 11s 19MB 16MB 1.0 0/15000060 0/15000198 OK node 10 P7XDJA 2019-04-03 05:28:36+03 FULL STREAM 1/0 21s 32MB 16MB 1.0 0/13000028 0/13000198 OK
The Time field for the merged backup displays the time
required for the merge.
If you need to keep certain backups longer than the established retention policy allows, you can pin them for arbitrary time. For example:
lt_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--ttl=30d
This command sets the expiration time of the
specified backup to 30 days starting from the time
indicated in its recovery-time attribute.
You can also explicitly set the expiration time for a backup
using the --expire-time option. For example:
lt_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--expire-time="2020-01-01 00:00:00+03"
Alternatively, you can use the --ttl and
--expire-time options with the
backup command to pin the newly
created backup:
lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --ttl=30d lt_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --expire-time="2020-01-01 00:00:00+03"
To check if the backup is pinned, run the show command:
lt_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
If the backup is pinned, it has the expire-time
attribute that displays its expiration time:
... recovery-time = '2017-05-16 12:57:31' expire-time = '2020-01-01 00:00:00+03' data-bytes = 22288792 ...
You can unpin the backup by setting the --ttl option to zero:
lt_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--ttl=0
A pinned incremental backup implicitly pins all its parent backups. If you unpin such a backup later, its implicitly pinned parents will also be automatically unpinned.
When continuous
WAL archiving is enabled, archived WAL segments can take a lot
of disk space. Even if you delete old backup copies from time to time,
the --delete-wal flag can
purge only those WAL segments that do not apply to any of the
remaining backups in the backup catalog. However, if point-in-time
recovery is critical only for the most recent backups, you can
configure WAL archive retention policy to keep WAL archive of
limited depth and win back some more disk space.
To configure WAL archive retention policy, you have to run the
set-config command with the
--wal-depth option that specifies the number
of backups that can be used for PITR.
This setting applies to all the timelines, so you should be able to perform
PITR for the same number of backups on each timeline, if available.
Pinned backups are
not included into this count: if one of the latest backups
is pinned, lt_probackup ensures that
PITR is possible for one extra backup.
To remove WAL segments that do not satisfy the defined WAL archive
retention policy, you simply have to run the delete
or backup command with the --delete-wal
flag. For archive backups, WAL segments between Start LSN
and Stop LSN are always kept intact, so such backups
remain valid regardless of the --wal-depth setting
and can still be restored, if required.
You can also use the --wal-depth option
with the delete and backup
commands to override the previously defined WAL archive retention
policy and purge old WAL segments on the fly.
Suppose you have backed up the node
instance in the backup_dir directory and
configured
continuous WAL
archiving:
lt_probackup show -Bbackup_dir--instancenode
BACKUP INSTANCE 'node' ==================================================================================================================================== Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zratio Start LSN Stop LSN Status ==================================================================================================================================== node 11 PZ9442 2019-10-12 10:43:21+03 DELTA STREAM 1/0 10s 121kB 16MB 1.00 0/46000028 0/46000160 OK node 11 PZ943L 2019-10-12 10:43:04+03 FULL STREAM 1/0 10s 180MB 32MB 1.00 0/44000028 0/44000160 OK node 11 PZ7YR5 2019-10-11 19:49:56+03 DELTA STREAM 1/1 10s 112kB 32MB 1.00 0/41000028 0/41000160 OK node 11 PZ7YMP 2019-10-11 19:47:16+03 DELTA STREAM 1/1 10s 376kB 32MB 1.00 0/3E000028 0/3F0000B8 OK node 11 PZ7YK2 2019-10-11 19:45:45+03 FULL STREAM 1/0 11s 180MB 16MB 1.00 0/3C000028 0/3C000198 OK node 11 PZ7YFO 2019-10-11 19:43:04+03 FULL STREAM 1/0 10s 30MB 16MB 1.00 0/2000028 0/200ADD8 OK
You can check the state of the WAL archive by running the
show command with the
--archive flag:
lt_probackup show -B backup_dir --instance node --archive
ARCHIVE INSTANCE 'node' =============================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zratio N backups Status =============================================================================================================================== 1 0 0/0 000000010000000000000001 000000010000000000000047 71 36MB 31.00 6 OK
WAL purge without --wal-depth cannot
achieve much, only one segment is removed:
lt_probackup delete -B backup_dir --instance node --delete-wal
ARCHIVE INSTANCE 'node' =============================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zratio N backups Status =============================================================================================================================== 1 0 0/0 000000010000000000000002 000000010000000000000047 70 34MB 32.00 6 OK
If you would like, for example, to keep only those WAL
segments that can be applied to the latest valid backup, set the
--wal-depth option to 1:
lt_probackup delete -B backup_dir --instance node --delete-wal --wal-depth=1
ARCHIVE INSTANCE 'node' ================================================================================================================================ TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zratio N backups Status ================================================================================================================================ 1 0 0/0 000000010000000000000046 000000010000000000000047 2 143kB 228.00 6 OK
Alternatively, you can use the --wal-depth
option with the backup command:
lt_probackup backup -B backup_dir --instance node -b DELTA --wal-depth=1 --delete-wal
ARCHIVE INSTANCE 'node' =============================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zratio N backups Status =============================================================================================================================== 1 0 0/0 000000010000000000000048 000000010000000000000049 1 72kB 228.00 7 OK
As you take more and more incremental backups, the total size of
the backup catalog can substantially grow. To save disk space,
you can merge incremental backups to their parent full backup by
running the merge command, specifying the backup ID of the most
recent incremental backup you would like to merge:
lt_probackup merge -Bbackup_dir--instanceinstance_name-ibackup_id
This command merges backups that belong to a common incremental backup chain. If you specify a full backup, it will be merged with its first incremental backup. If you specify an incremental backup, it will be merged to its parent full backup, together with all incremental backups between them. Once the merge is complete, the full backup takes in all the merged data, and the incremental backups are removed as redundant. Thus, the merge operation is virtually equivalent to retaking a full backup and removing all the outdated backups, but it allows to save much time, especially for large data volumes, as well as I/O and network traffic if you are using lt_probackup in the remote mode.
Before the merge, lt_probackup validates all the affected backups to ensure that they are valid. You can check the current backup status by running the show command with the backup ID:
lt_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
If the merge is still in progress, the backup status is
displayed as MERGING. For full backups,
it can also be shown as MERGED while the
metadata is being updated at the final stage of the merge.
The merge is idempotent, so you can
restart the merge if it was interrupted.
To delete a backup that is no longer required, run the following command:
lt_probackup delete -Bbackup_dir--instanceinstance_name-ibackup_id
This command will delete the backup with the specified
backup_id, together with all the
incremental backups that descend from
backup_id, if any. This way you can delete
some recent incremental backups, retaining the underlying full
backup and some of the incremental backups that follow it.
To delete obsolete WAL files that are not necessary to restore
any of the remaining backups, use the
--delete-wal flag:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-wal
To delete backups that are expired according to the current
retention policy, use the --delete-expired
flag:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired
Expired backups cannot be removed while at least one
incremental backup that satisfies the retention policy is based
on them. If you would like to minimize the number of backups
still required to keep incremental backups valid, specify the
--merge-expired flag when running this
command:
lt_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --merge-expired
In this case, lt_probackup searches for the oldest incremental backup that satisfies the retention policy and merges this backup with the underlying full and incremental backups that have already expired, thus making it a full backup. Once the merge is complete, the remaining expired backups are deleted.
Before merging or deleting backups, you can run the
delete command with the
--dry-run flag, which displays the status of
all the available backups according to the current retention
policy, without performing any irreversible actions.
To delete all backups with specific status, use the --status:
lt_probackup delete -Bbackup_dir--instanceinstance_name--status=ERROR
Deleting backups by status ignores established retention policies.
This section describes lt_probackup commands. Optional parameters are enclosed in square brackets. For detailed parameter descriptions, see the section Options.
lt_probackup version
Prints lt_probackup version.
lt_probackup help [command]
Displays the synopsis of lt_probackup commands. If one of the lt_probackup commands is specified, shows detailed information about the options that can be used with this command.
lt_probackup init -B backup_dir [--help]
Initializes the backup catalog in
backup_dir that will store backup copies,
WAL archive, and meta information for the backed up database
clusters. If the specified backup_dir
already exists, it must be empty. Otherwise, lt_probackup
displays a corresponding error message.
For details, see the section Initializing the Backup Catalog.
lt_probackup add-instance -Bbackup_dir-Ddata_dir--instanceinstance_name[--help]
Initializes a new backup instance inside the backup catalog
backup_dir and generates the
pg_probackup.conf configuration file that controls
lt_probackup settings for the cluster with the specified
data_dir data directory.
For details, see the section Adding a New Backup Instance.
lt_probackup del-instance -Bbackup_dir--instanceinstance_name[--help]
Deletes all backups and WAL files associated with the specified instance.
lt_probackup set-config -Bbackup_dir--instanceinstance_name[--help] [--pgdata=pgdata-path] [--retention-redundancy=redundancy][--retention-window=window][--wal-depth=wal_depth] [--compress-algorithm=compression_algorithm] [--compress-level=compression_level] [-ddbname] [-hhost] [-pport] [-Uusername] [--archive-timeout=timeout] [--external-dirs=external_directory_path] [--restore-command=cmdline] [remote_options] [remote_wal_archive_options] [logging_options]
Adds the specified connection, compression, retention, logging,
and external directory settings into the pg_probackup.conf
configuration file, or modifies the previously defined values.
For all available settings, see the Options section.
It is not recommended to
edit pg_probackup.conf manually.
lt_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id{--ttl=ttl| --expire-time=time} [--note=backup_note] [--help]
Sets the provided backup-specific settings into the
backup.control configuration file, or modifies the previously
defined values.
--note=backup_note
Sets the text note for backup copy.
If backup_note contain newline characters,
then only substring before first newline character will be saved.
Max size of text note is 1 KB.
The 'none' value removes current note.
For all available pinning settings, see the section Pinning Options.
lt_probackup show-config -Bbackup_dir--instanceinstance_name[--format=plain|json]
Displays the contents of the pg_probackup.conf configuration
file located in the
backup_dir/backups/instance_name--format=json option to get the result
in the JSON format. By default, configuration settings are
shown as plain text.
To edit pg_probackup.conf, use the
set-config command.
lt_probackup show -Bbackup_dir[--help] [--instanceinstance_name[-ibackup_id| --archive]] [--format=plain|json]
Shows the contents of the backup catalog. If
instance_name and
backup_id are specified, shows detailed
information about this backup. If the --archive option is
specified, shows the contents of WAL archive of the backup
catalog.
By default, the contents of the backup catalog is shown as
plain text. You can specify the
--format=json option to get the result
in the JSON format.
For details on usage, see the sections Managing the Backup Catalog and Viewing WAL Archive Information.
lt_probackup backup -Bbackup_dir-bbackup_mode--instanceinstance_name[--help] [-jnum_threads] [--progress] [-C] [--stream [-S slot_name] [--temp-slot]] [--backup-pg-log] [--no-validate] [--skip-block-validation] [-w --no-password] [-W --password] [--archive-timeout=timeout] [--external-dirs=external_directory_path] [--no-sync] [--note=backup_note] [connection_options] [compression_options] [remote_options] [retention_options] [pinning_options] [logging_options]
Creates a backup copy of the LightDB instance.
-b mode--backup-mode=modeSpecifies the backup mode to use. Possible values are:
FULL — creates a full backup that contains all the data
files of the cluster to be restored.
DELTA — reads all data files in the data directory and
creates an incremental backup for pages that have changed
since the previous backup.
PAGE — creates an incremental PAGE backup based on the WAL
files that have changed since the previous full or
incremental backup was taken.
PTRACK — creates an incremental PTRACK backup tracking
page changes on the fly.
-C--smooth-checkpointSpreads out the checkpoint over a period of time. By default, lt_probackup tries to complete the checkpoint as soon as possible.
--streamMakes a STREAM backup, which includes all the necessary WAL files by streaming them from the database server via replication protocol.
--temp-slot
Creates a temporary physical replication slot for streaming
WAL from the backed up LightDB instance. It ensures that
all the required WAL segments remain available if WAL is
rotated while the backup is in progress. This flag can only be
used together with the --stream flag.
The default slot name is lt_probackup_slot,
which can be changed using the --slot/-S option.
-S slot_name--slot=slot_name
Specifies the replication slot for WAL streaming. This option
can only be used together with the --stream
flag.
--backup-pg-logIncludes the log directory into the backup. This directory usually contains log messages. By default, log directory is excluded.
-E external_directory_path--external-dirs=external_directory_pathIncludes the specified directory into the backup by recursively copying its contents into a separate subdirectory in the backup catalog. This option is useful to back up scripts, SQL dump files, and configuration files located outside of the data directory. If you would like to back up several external directories, separate their paths by a colon on Unix.
--archive-timeout=wait_timeSets the timeout for WAL segment archiving and streaming, in seconds. By default, lt_probackup waits 300 seconds.
--skip-block-validationDisables block-level checksum verification to speed up the backup process.
--no-validateSkips automatic validation after the backup is taken. You can use this flag if you validate backups regularly and would like to save time when running backup operations.
--no-syncDo not sync backed up files to disk. You can use this flag to speed up the backup process. Using this flag can result in data corruption in case of operating system or hardware crash. If you use this option, it is recommended to run the validate command once the backup is complete to detect possible issues.
--note=backup_note
Sets the text note for backup copy.
If backup_note contain newline characters,
then only substring before first newline character will be saved.
Max size of text note is 1 KB.
The 'none' value removes current note.
Additionally, connection options, retention options, pinning options, remote mode options, compression options, logging options, and common options can be used.
For details on usage, see the section Creating a Backup.
lt_probackup restore -Bbackup_dir--instanceinstance_name[--help] [-Ddata_dir] [-ibackup_id] [-jnum_threads] [--progress] [-TOLDDIR=NEWDIR] [--external-mapping=OLDDIR=NEWDIR] [--skip-external-dirs] [-R | --restore-as-replica] [--no-validate] [--skip-block-validation] [--force] [--no-sync] [--restore-command=cmdline] [--primary-conninfo=primary_conninfo] [-S | --primary-slot-name=slot_name] [recovery_target_options] [logging_options] [remote_options] [partial_restore_options] [remote_wal_archive_options]
Restores the LightDB instance from a backup copy located in
the backup_dir backup catalog. If you
specify a recovery
target option, lt_probackup finds the closest
backup and restores it to the specified recovery target.
If neither the backup ID nor recovery target options are provided,
lt_probackup uses the most recent backup
to perform the recovery.
-R--restore-as-replica
Creates a minimal recovery configuration file to facilitate setting up a
standby server. If the replication connection requires a password,
you must specify the password manually in the
primary_conninfo
parameter as it is not included.
lt_probackup writes these settings into
the probackup_recovery.conf file in the data
directory, and then includes them into the
lightdb.auto.conf when the cluster is
is started.
--primary-conninfo=primary_conninfo
Sets the
primary_conninfo
parameter to the specified value.
This option will be ignored unless the -R flag is specified.
Example: --primary-conninfo="host=192.168.1.50 port=5432 user=foo password=foopass"
-S--primary-slot-name=slot_name
Sets the
primary_slot_name
parameter to the specified value.
This option will be ignored unless the -R flag is specified.
-T OLDDIR=NEWDIR--tablespace-mapping=OLDDIR=NEWDIR
Relocates the tablespace from the OLDDIR to the NEWDIR
directory at the time of recovery. Both OLDDIR and NEWDIR must
be absolute paths. If the path contains the equals sign (=),
escape it with a backslash. This option can be specified
multiple times for multiple tablespaces.
--external-mapping=OLDDIR=NEWDIR
Relocates an external directory included into the backup from
the OLDDIR to the NEWDIR directory at the time of recovery.
Both OLDDIR and NEWDIR must be absolute paths. If the path
contains the equals sign (=), escape it with a backslash. This
option can be specified multiple times for multiple
directories.
--skip-external-dirs
Skip external directories included into the backup with the
--external-dirs option. The contents of
these directories will not be restored.
--skip-block-validationDisables block-level checksum verification to speed up validation. During automatic validation before the restore only file-level checksums will be verified.
--no-validateSkips backup validation. You can use this flag if you validate backups regularly and would like to save time when running restore operations.
--restore-command=cmdline
Sets the
restore_command
parameter to the specified command. For example:
--restore-command='cp /mnt/server/archivedir/%f "%p"'
--force
Allows to ignore an invalid status of the backup. You can use
this flag if you need to restore the
LightDB cluster from a corrupt or an invalid backup.
Use with caution.
If LTDATA contains a non-empty directory with system ID different from that
of the backup being restored, incremental restore
with this flag overwrites the directory contents (while an error occurs without the flag). If tablespaces
are remapped through the --tablespace-mapping option into non-empty directories,
the contents of such directories will be deleted.
--no-syncDo not sync restored files to disk. You can use this flag to speed up restore process. Using this flag can result in data corruption in case of operating system or hardware crash. If it happens, you have to run the restore command again.
Additionally, recovery target options, remote mode options, remote WAL archive options, logging options, partial restore options, and common options can be used.
For details on usage, see the section Restoring a Cluster.
lt_probackup checkdb [-Bbackup_dir] [--instanceinstance_name] [-Ddata_dir] [--help] [-jnum_threads] [--progress] [--skip-block-validation] [--amcheck] [--heapallindexed] [connection_options] [logging_options]
Verifies the LightDB database instance correctness by detecting physical and logical corruption.
--amcheckPerforms logical verification of indexes for the specified LightDB instance if no corruption was found while checking data files. You must have the amcheck extension or the amcheck_next extension installed in the database to check its indexes. For databases without amcheck, index verification will be skipped.
--skip-block-validation
Skip validation of data files. You can use this flag only
together with the --amcheck flag, so that only logical
verification of indexes is performed.
--heapallindexed
Checks that all heap tuples that should be indexed are
actually indexed. You can use this flag only together with the
--amcheck flag.
This check is only possible if you are using the amcheck extension of version 3.0 or higher, or the amcheck_next extension of any version.
Additionally, connection options and logging options can be used.
For details on usage, see the section Verifying a Cluster.
lt_probackup validate -Bbackup_dir[--help] [--instanceinstance_name] [-ibackup_id] [-jnum_threads] [--progress] [--skip-block-validation] [recovery_target_options] [logging_options]
Verifies that all the files required to restore the cluster
are present and are not corrupt. If
instance_name is not specified,
lt_probackup validates all backups available in the backup
catalog. If you specify the instance_name
without any additional options, lt_probackup validates all the
backups available for this backup instance. If you specify the
instance_name with a
recovery target
option and/or a backup_id,
lt_probackup checks whether it is possible to restore the
cluster using these options.
For details, see the section Validating a Backup.
lt_probackup merge -Bbackup_dir--instanceinstance_name-ibackup_id[--help] [-jnum_threads] [--progress] [--no-validate] [--no-sync] [logging_options]
Merges backups that belong to a common incremental backup chain. If you specify a full backup, it will be merged with its first incremental backup. If you specify an incremental backup, it will be merged to its parent full backup, together with all incremental backups between them. Once the merge is complete, the full backup takes in all the merged data, and the incremental backups are removed as redundant.
--no-validateSkips automatic validation before and after merge.
--no-syncDo not sync merged files to disk. You can use this flag to speed up the merge process. Using this flag can result in data corruption in case of operating system or hardware crash.
For details, see the section Merging Backups.
lt_probackup delete -Bbackup_dir--instanceinstance_name[--help] [-jnum_threads] [--progress] [--retention-redundancy=redundancy][--retention-window=window][--wal-depth=wal_depth] [--delete-wal] {-ibackup_id| --delete-expired [--merge-expired] | --merge-expired | --status=backup_status} [--dry-run] [--no-validate] [--no-sync] [logging_options]
Deletes backup with specified backup_id
or launches the retention purge of backups and archived WAL
that do not satisfy the current retention policies.
--no-validateSkips automatic validation before and after retention merge.
--no-syncDo not sync merged files to disk. You can use this flag to speed up the retention merge process. Using this flag can result in data corruption in case of operating system or hardware crash.
For details, see the sections Deleting Backups, Retention Options and Configuring Retention Policy.
lt_probackup archive-push -Bbackup_dir--instanceinstance_name--wal-file-name=wal_file_name[--wal-file-path=wal_file_path] [--help] [--no-sync] [--compress] [--no-ready-rename] [--overwrite] [-jnum_threads] [--batch-size=batch_size] [--archive-timeout=timeout] [--compress-algorithm=compression_algorithm] [--compress-level=compression_level] [remote_options] [logging_options]
Copies WAL files into the corresponding subdirectory of the
backup catalog and validates the backup instance by
instance_name and
system-identifier. If parameters of the
backup instance and the cluster do not match, this command
fails with the following error message: Refuse to push WAL
segment segment_name into archive. Instance parameters
mismatch.
If the files to be copied already exists in the backup catalog,
lt_probackup computes and compares their checksums. If the
checksums match, archive-push skips the corresponding file and
returns a successful execution code. Otherwise, archive-push
fails with an error. If you would like to replace WAL files in
the case of checksum mismatch, run the archive-push command
with the --overwrite flag.
Each file is copied to a temporary file with the
.part suffix. If the temporary file already
exists, lt_probackup will wait
archive_timeout seconds before discarding it.
After the copy is done, atomic rename is performed.
This algorithm ensures that a failed archive-push
will not stall continuous archiving and that concurrent archiving from
multiple sources into a single WAL archive has no risk of archive
corruption.
To speed up archiving, you can specify the --batch-size option
to copy WAL segments in batches of the specified size.
If --batch-size option is used, then you can also specify
the -j option to copy the batch of WAL segments on multiple threads.
WAL segments copied to the archive are synced to disk unless
the --no-sync flag is used.
You can use archive-push in the
archive_command
LightDB parameter to set up
continuous
WAL archiving.
For details, see sections Archiving Options and Compression Options.
lt_probackup archive-get -Bbackup_dir--instanceinstance_name--wal-file-path=wal_file_path--wal-file-name=wal_file_name[-jnum_threads] [--batch-size=batch_size] [--prefetch-dir=prefetch_dir_path] [--no-validate-wal] [--help] [remote_options] [logging_options]
Copies WAL files from the corresponding subdirectory of the
backup catalog to the cluster's write-ahead log location. This
command is automatically set by lt_probackup as part of the
restore_command when
restoring backups using a WAL archive. You do not need to set
it manually.
To speed up recovery, you can specify the --batch-size option
to copy WAL segments in batches of the specified size.
If --batch-size option is used, then you can also specify
the -j option to copy the batch of WAL segments on multiple threads.
For details, see section Archiving Options.
This section describes command-line options for lt_probackup
commands. If the option value can be derived from an environment
variable, this variable is specified below the command-line
option, in the uppercase. Some values can be taken from the
pg_probackup.conf configuration file located in the backup
catalog.
For details, see the section called “Configuring lt_probackup”.
If an option is specified using more than one method,
command-line input has the highest priority, while the
pg_probackup.conf settings have the lowest priority.
The list of general options.
-B directory--backup-path=directoryBACKUP_PATH
Specifies the absolute path to the backup catalog. Backup
catalog is a directory where all backup files and meta
information are stored. Since this option is required for most
of the lt_probackup commands, you are recommended to specify
it once in the BACKUP_PATH environment variable. In this case,
you do not need to use this option each time on the command
line.
-D directory--pgdata=directoryLTDATA
Specifies the absolute path to the data directory of the
database instance. This option is mandatory only for the
add-instance command.
Other commands can take its value from the LTDATA environment
variable, or from the pg_probackup.conf configuration file.
-i backup_id--backup-id=backup_idSpecifies the unique identifier of the backup.
-j num_threads--threads=num_threads
Sets the number of parallel threads for backup,
restore, merge,
validate, checkdb, and
archive-push processes.
--progressShows the progress of operations.
--helpShows detailed information about the options that can be used with this command.
If continuous WAL archiving is configured, you can use one of these options together with restore or validate commands to specify the moment up to which the database instance must be restored or validated.
--recovery-target=immediate|latestDefines when to stop the recovery:
The immediate value stops the recovery
after reaching the consistent state of the specified
backup, or the latest available backup if the
-i/--backup-id option is omitted.
This is the default behavior for STREAM backups.
The latest value continues the recovery
until all WAL segments available in the archive are
applied. This is the default behavior for ARCHIVE backups.
--recovery-target-timeline=timelineSpecifies a particular timeline to be used for recovery. By default, the timeline of the specified backup is used.
--recovery-target-lsn=lsnSpecifies the LSN of the write-ahead log location up to which recovery will proceed. Can be used only when restoring a database instance of major version 10 or higher.
--recovery-target-name=recovery_target_nameSpecifies a named savepoint up to which to restore the cluster.
--recovery-target-time=timeSpecifies the timestamp up to which recovery will proceed. If the time zone offset is not specified, the local time zone is used.
Example: --recovery-target-time="2020-01-01 00:00:00+03"
--recovery-target-xid=xidSpecifies the transaction ID up to which recovery will proceed.
--recovery-target-inclusive=boolean
Specifies whether to stop just after the specified recovery
target (true), or just before the recovery target (false).
This option can only be used together with
--recovery-target-name,
--recovery-target-time,
--recovery-target-lsn or
--recovery-target-xid options. The default
depends on the
recovery_target_inclusive
parameter.
--recovery-target-action=pause|promote|shutdownSpecifies the action the server should take when the recovery target is reached.
Default: pause
You can use these options together with backup and delete commands.
For details on configuring retention policy, see the section Configuring Retention Policy.
--retention-redundancy=redundancySpecifies the number of full backup copies to keep in the data directory. Must be a non-negative integer. The zero value disables this setting.
Default: 0
--retention-window=windowNumber of days of recoverability. Must be a non-negative integer. The zero value disables this setting.
Default: 0
--wal-depth=wal_depthNumber of latest valid backups on every timeline that must retain the ability to perform PITR. Must be a non-negative integer. The zero value disables this setting.
Default: 0
--delete-walDeletes WAL files that are no longer required to restore the cluster from any of the existing backups.
--delete-expired
Deletes backups that do not conform to the retention policy
defined in the pg_probackup.conf configuration file.
--merge-expiredMerges the oldest incremental backup that satisfies the requirements of retention policy with its parent backups that have already expired.
--dry-runDisplays the current status of all the available backups, without deleting or merging expired backups, if any.
You can use these options together with backup and set-backup commands.
For details on backup pinning, see the section Backup Pinning.
--ttl=ttlSpecifies the amount of time the backup should be pinned. Must be a non-negative integer. The zero value unpins the already pinned backup. Supported units: ms, s, min, h, d (s by default).
Example: --ttl=30d
--expire-time=timeSpecifies the timestamp up to which the backup will stay pinned. Must be an ISO-8601 complaint timestamp. If the time zone offset is not specified, the local time zone is used.
Example: --expire-time="2020-01-01 00:00:00+03"
You can use these options with any command.
--log-level-console=log_level
Controls which message levels are sent to the console log.
Valid values are verbose,
log, info,
warning, error and
off. Each level includes all the levels
that follow it. The later the level, the fewer messages are
sent. The off level disables console
logging.
Default: info
All console log messages are going to stderr, so the output of show and show-config commands does not mingle with log messages.
--log-level-file=log_level
Controls which message levels are sent to a log file. Valid
values are verbose, log,
info, warning,
error, and off. Each
level includes all the levels that follow it. The later the
level, the fewer messages are sent. The off
level disables file logging.
Default: off
--log-filename=log_filename
Defines the filenames of the created log files. The filenames
are treated as a strftime pattern, so you can use %-escapes to
specify time-varying filenames.
Default: pg_probackup.log
For example, if you specify the lt_probackup-%u.log pattern,
lt_probackup generates a separate log file for each day of the
week, with %u replaced by the corresponding decimal number:
lt_probackup-1.log for Monday, lt_probackup-2.log for Tuesday,
and so on.
This option takes effect if file logging is enabled by the
--log-level-file option.
--error-log-filename=error_log_filename
Defines the filenames of log files for error messages only.
The filenames are treated as a strftime pattern, so you can
use %-escapes to specify time-varying filenames.
Default: none
For example, if you specify the error-lt_probackup-%u.log
pattern, lt_probackup generates a separate log file for each
day of the week, with %u replaced by the corresponding decimal
number: error-lt_probackup-1.log for Monday,
error-lt_probackup-2.log for Tuesday, and so on.
This option is useful for troubleshooting and monitoring.
--log-directory=log_directoryDefines the directory in which log files will be created. You must specify the absolute path. This directory is created lazily, when the first log message is written.
Default: $BACKUP_PATH/log/
--log-rotation-size=log_rotation_size
Maximum size of an individual log file. If this value is
reached, the log file is rotated once a lt_probackup command
is launched, except help and version commands. The zero value
disables size-based rotation. Supported units: kB, MB, GB, TB
(kB by default).
Default: 0
--log-rotation-age=log_rotation_age
Maximum lifetime of an individual log file. If this value is
reached, the log file is rotated once a lt_probackup command
is launched, except help and version commands. The time of the
last log file creation is stored in
$BACKUP_PATH/log/log_rotation. The zero value disables
time-based rotation. Supported units: ms, s, min, h, d (min by
default).
Default: 0
You can use these options together with backup and checkdb commands.
All libpq environment variables are supported.
-d dbname--pgdatabase=dbnameLTDATABASE
Specifies the name of the database to connect to. The
connection is used only for managing backup process, so you
can connect to any existing database. If this option is not
provided on the command line, LTDATABASE environment variable,
or the pg_probackup.conf configuration file, lt_probackup
tries to take this value from the LTUSER environment variable,
or from the current user name if LTUSER variable is not set.
-h host--pghost=hostLTHOSTSpecifies the host name of the system on which the server is running. If the value begins with a slash, it is used as a directory for the Unix domain socket.
Default: localhost
-p port--pgport=portLTPORTSpecifies the TCP port or the local Unix domain socket file extension on which the server is listening for connections.
Default: 5432
-U username--pguser=usernameLTUSERUser name to connect as.
-w--no-password
Disables a password prompt. If the server requires password
authentication and a password is not available by other means
such as a
.pgpass
file or PGPASSWORD environment variable, the connection
attempt will fail. This flag can be useful in batch jobs and
scripts where no user is present to enter a password.
-W--passwordForces a password prompt. (Deprecated)
You can use these options together with backup and archive-push commands.
--compress-algorithm=compression_algorithm
Defines the algorithm to use for compressing data files.
Possible values are zlib,
pglz, and none. If set
to zlib or pglz, this option enables compression. By default,
compression is disabled. For the
archive-push command, the
pglz compression algorithm is not supported.
Default: none
--compress-level=compression_level
Defines compression level (0 through 9, 0 being no compression
and 9 being best compression). This option can be used
together with the --compress-algorithm option.
Default: 1
--compress
Alias for --compress-algorithm=zlib and
--compress-level=1.
These options can be used with the archive-push command in the archive_command setting and the archive-get command in the restore_command setting.
Additionally, remote mode options and logging options can be used.
--wal-file-path=wal_file_path
Provides the path to the WAL file in
archive_command and
restore_command. Use the %p
variable as the value for this option for correct processing.
--wal-file-name=wal_file_name
Provides the name of the WAL file in
archive_command and
restore_command. Use the %f
variable as the value for this option for correct processing.
--overwrite
Overwrites archived WAL file. Use this flag together with the
archive-push command if
the specified subdirectory of the backup catalog already
contains this WAL file and it needs to be replaced with its
newer copy. Otherwise, archive-push reports that a WAL segment
already exists, and aborts the operation. If the file to
replace has not changed, archive-push skips this file
regardless of the --overwrite flag.
--batch-size=batch_size
Sets the maximum number of files that can be copied into the archive
by a single archive-push process, or from
the archive by a single archive-get process.
--archive-timeout=wait_time
Sets the timeout for considering existing .part
files to be stale. By default, lt_probackup
waits 300 seconds.
This option can be used only with archive-push command.
--no-ready-rename
Do not rename status files in the archive_status directory.
This option should be used only if archive_command
contains multiple commands.
This option can be used only with archive-push command.
--no-syncDo not sync copied WAL files to disk. You can use this flag to speed up archiving process. Using this flag can result in WAL archive corruption in case of operating system or hardware crash. This option can be used only with archive-push command.
--prefetch-dir=path
Directory used to store prefetched WAL segments if --batch-size option is used.
Directory must be located on the same filesystem and on the same mountpoint the
LTDATA/lt_wal is located.
By default files are stored in LTDATA/lt_wal/pbk_prefetch directory.
This option can be used only with archive-get command.
--no-validate-walDo not validate prefetched WAL file before using it. Use this option if you want to increase the speed of recovery. This option can be used only with archive-get command.
This section describes the options related to running lt_probackup operations remotely via SSH. These options can be used with add-instance, set-config, backup, restore, archive-push, and archive-get commands.
For details on configuring and using the remote mode, see the section called “Configuring the Remote Mode” and the section called “Using lt_probackup in the Remote Mode”.
--remote-proto=protoSpecifies the protocol to use for remote operations. Currently only the SSH protocol is supported. Possible values are:
ssh enables the remote mode via
SSH. This is the default value.
none explicitly disables the remote
mode.
You can omit this option if the
--remote-host option is specified.
--remote-host=destinationSpecifies the remote host IP address or hostname to connect to.
--remote-port=portSpecifies the remote host port to connect to.
Default: 22
--remote-user=usernameSpecifies remote host user for SSH connection. If you omit this option, the current user initiating the SSH connection is used.
--remote-path=pathSpecifies lt_probackup installation directory on the remote system.
--ssh-options=ssh_options
Provides a string of SSH command-line options. For example,
the following options can be used to set keep-alive for SSH
connections opened by lt_probackup:
--ssh-options="-o ServerAliveCountMax=5 -o ServerAliveInterval=60".
For the full list of possible options, see
ssh_config
manual page.
This section describes the options used to provide the arguments for remote mode options in archive-get used in the restore_command command when restoring ARCHIVE backups or performing PITR.
--archive-host=destination
Provides the argument for the --remote-host
option in the archive-get command.
--archive-port=port
Provides the argument for the --remote-port
option in the archive-get command.
Default: 22
--archive-user=username
Provides the argument for the --remote-user
option in the archive-get command. If you omit
this option, the user that has started the LightDB cluster is used.
Default: LightDB user
This section describes the options for incremental cluster restore. These options can be used with the restore command.
-I incremental_mode--incremental-mode=incremental_modeSpecifies the incremental mode to be used. Possible values are:
CHECKSUM — replace only pages with mismatched checksum and LSN.
LSN — replace only pages with LSN greater than point of divergence.
NONE — regular restore.
This section describes the options for partial cluster restore. These options can be used with the restore command.
--db-exclude=dbname
Specifies the name of the database to exclude from restore. All other
databases in the cluster will be restored as usual, including
template0 and template1.
This option can be specified multiple times for multiple
databases.
--db-include=dbname
Specifies the name of the database to restore from a backup. All other
databases in the cluster will not be restored, with the exception
of template0 and
template1. This option can be specified
multiple times for multiple databases.
This section describes the options related to taking a backup from standby.
Starting from lt_probackup 2.0.24, backups can be taken from standby without connecting to the master server, so these options are no longer required. In lower versions, lt_probackup had to connect to the master to determine recovery time — the earliest moment for which you can restore a consistent state of the database instance.
--master-db=dbname
Deprecated. Specifies the name of the database on the master
server to connect to. The connection is used only for managing
the backup process, so you can connect to any existing
database. Can be set in the pg_probackup.conf using the
set-config command.
Default: postgres, the default LightDB database
--master-host=hostDeprecated. Specifies the host name of the system on which the master server is running.
--master-port=portDeprecated. Specifies the TCP port or the local Unix domain socket file extension on which the master server is listening for connections.
Default: 5432, the LightDB default port
--master-user=usernameDeprecated. User name to connect as.
Default: lightdb,
the LightDB default user name
--replica-timeout=timeout
Deprecated. Wait time for WAL segment streaming via
replication, in seconds. By default, lt_probackup waits 300
seconds. You can also define this parameter in the
pg_probackup.conf configuration file using the
set-config command.
Default: 300 sec
All examples below assume the remote mode of operations via
SSH. If you are planning to run backup and
restore operation locally, skip the
“Setup passwordless SSH connection” step
and omit all --remote-* options.
Examples are based on Centos 7.9, LightDB 22.3, and lt_probackup 2.4.15.
backup — LightDB
role used for connection to LightDB
cluster.
backupdb — database used for connection
to LightDB cluster.
backup_host — host with backup catalog.
backupman — user on
backup_host running all lt_probackup
operations.
/mnt/backups — directory on
backup_host where backup catalog is stored.
lightdb_host — host with LightDB
cluster.
lightdb — user on
lightdb_host that has started the LightDB cluster.
/var/lib/postgresql/11/main — LightDB
data directory on lightdb_host.
This scenario illustrates setting up standalone FULL and DELTA backups.
Set up passwordless SSH connection from
backup_host to
lightdb_host:
[backupman@backup_host] ssh-copy-id lightdb@lightdb_host
Configure your LightDB cluster.
For security purposes, it is recommended to use a separate database for backup operations.
lightdb@postgres=# CREATE DATABASE backupdb;
Connect to the backupdb database, create the
probackup role, and grant the following
permissions to this role:
backupdb=# BEGIN; CREATE ROLE backup REPLICATION; GRANT USAGE ON SCHEMA pg_catalog TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.current_setting(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_is_in_recovery() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_start_backup(text, boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_stop_backup(boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_create_restore_point(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_switch_wal() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_last_wal_replay_lsn() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current_snapshot() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_snapshot_xmax(txid_snapshot) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_control_checkpoint() TO backup; COMMIT;
Initialize the backup catalog:
[backupman@backup_host]$ lt_probackup init -B /mnt/backups INFO: Backup catalog '/mnt/backups' successfully inited
Add instance node to the backup catalog:
[backupman@backup_host]$ lt_probackup add-instance -B /mnt/backups --instance node --remote-host=lightdb_host --remote-user=lightdb -D /var/lib/postgresql/11/main INFO: Instance 'node' successfully inited
Take a FULL backup:
[backupman@backup_host] lt_probackup backup -B /mnt/backups --instance node -b FULL --stream --remote-host=lightdb_host --remote-user=lightdb -U backup -d backupdb INFO: Backup start, lt_probackup version: 2.4.15, instance: node, backup ID: PZ7YK2, backup mode: FULL, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: Start transferring data files INFO: Data files are transferred INFO: wait for pg_stop_backup() INFO: pg_stop backup() successfully executed INFO: Validating backup PZ7YK2 INFO: Backup PZ7YK2 data files are valid INFO: Backup PZ7YK2 resident size: 196MB INFO: Backup PZ7YK2 completed
Let's take a look at the backup catalog:
[backupman@backup_host] lt_probackup show -B /mnt/backups --instance node BACKUP INSTANCE 'node' ================================================================================================================================== Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zratio Start LSN Stop LSN Status ================================================================================================================================== node 13 PZ7YK2 2019-10-11 19:45:45+03 FULL STREAM 1/0 11s 180MB 16MB 1.00 0/3C000028 0/3C000198 OK
Take an incremental backup in the DELTA mode:
[backupman@backup_host] lt_probackup backup -B /mnt/backups --instance node -b delta --stream --remote-host=lightdb_host --remote-user=lightdb -U backup -d backupdb INFO: Backup start, lt_probackup version: 2.4.15, instance: node, backup ID: PZ7YMP, backup mode: DELTA, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: Parent backup: PZ7YK2 INFO: Start transferring data files INFO: Data files are transferred INFO: wait for pg_stop_backup() INFO: pg_stop backup() successfully executed INFO: Validating backup PZ7YMP INFO: Backup PZ7YMP data files are valid INFO: Backup PZ7YMP resident size: 32MB INFO: Backup PZ7YMP completed
Let's add some parameters to lt_probackup configuration file, so that you can omit them from the command line:
[backupman@backup_host] lt_probackup set-config -B /mnt/backups --instance node --remote-host=lightdb_host --remote-user=lightdb -U backup -d backupdb
Take another incremental backup in the DELTA mode, omitting some of the previous parameters:
[backupman@backup_host] lt_probackup backup -B /mnt/backups --instance node -b delta --stream INFO: Backup start, lt_probackup version: 2.4.15, instance: node, backup ID: PZ7YR5, backup mode: DELTA, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: Parent backup: PZ7YMP INFO: Start transferring data files INFO: Data files are transferred INFO: wait for pg_stop_backup() INFO: pg_stop backup() successfully executed INFO: Validating backup PZ7YR5 INFO: Backup PZ7YR5 data files are valid INFO: Backup PZ7YR5 resident size: 32MB INFO: Backup PZ7YR5 completed
Let's take a look at the instance configuration:
[backupman@backup_host] lt_probackup show-config -B /mnt/backups --instance node # Backup instance information pgdata = /var/lib/postgresql/11/main system-identifier = 6746586934060931492 xlog-seg-size = 16777216 # Connection parameters pgdatabase = backupdb pghost = lightdb_host pguser = backup # Replica parameters replica-timeout = 5min # Archive parameters archive-timeout = 5min # Logging parameters log-level-console = INFO log-level-file = OFF log-filename = lt_probackup.log log-rotation-size = 0 log-rotation-age = 0 # Retention parameters retention-redundancy = 0 retention-window = 0 wal-depth = 0 # Compression parameters compress-algorithm = none compress-level = 1 # Remote access parameters remote-proto = ssh remote-host = lightdb_host
Note that we are getting the default values for other options
that were not overwritten by the set-config command.
Let's take a look at the backup catalog:
[backupman@backup_host] lt_probackup show -B /mnt/backups --instance node ==================================================================================================================================== Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zratio Start LSN Stop LSN Status ==================================================================================================================================== node 11 PZ7YR5 2019-10-11 19:49:56+03 DELTA STREAM 1/1 10s 112kB 32MB 1.00 0/41000028 0/41000160 OK node 11 PZ7YMP 2019-10-11 19:47:16+03 DELTA STREAM 1/1 10s 376kB 32MB 1.00 0/3E000028 0/3F0000B8 OK node 11 PZ7YK2 2019-10-11 19:45:45+03 FULL STREAM 1/0 11s 180MB 16MB 1.00 0/3C000028 0/3C000198 OK