pgmoneta

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Restore ​

Restore a backup ​

We can restore a backup from the primary with the following command

pgmoneta-cli restore primary newest current /tmp

where

  • current means copy the Write-Ahead Log (WAL ), and restore to first stable checkpoint
  • name=X means copy the Write-Ahead Log (WAL ), and restore to the label specified
  • xid=X means copy the Write-Ahead Log (WAL ), and restore to the XID specified
  • time=X means copy the Write-Ahead Log (WAL ), and restore to the timestamp specified
  • lsn=X means copy the Write-Ahead Log (WAL ), and restore to the Log Sequence Number (LSN) specified
  • inclusive=X means that the restore is inclusive of the specified information
  • timeline=X means that the restore is done to the specified information timeline
  • action=X means which action should be executed after the restore (pause, shutdown)
  • primary means that the cluster is setup as a primary
  • replica means that the cluster is setup as a replica

More information

And, you will get output like

Header:
  ClientVersion: 0.20.0
  Command: 3
  Output: 0
  Timestamp: 20240928130406
Outcome:
  Status: true
  Time: 00:00:00
Request:
  Backup: newest
  Directory: /tmp
  Position: current
  Server: primary
Response:
  Backup: 20240928065644
  BackupSize: 8531968
  Comments: ''
  Compression: 2
  Encryption: 0
  MajorVersion: 17
  MinorVersion: 0
  RestoreSize: 48799744
  Server: primary
  ServerVersion: 0.20.0

This command take the latest backup and all Write-Ahead Log (WAL) segments and restore it into the /tmp/primary-20240928065644 directory for an up-to-date copy.

Hot standby ​

In order to use hot standby, simply add

hot_standby = /your/local/hot/standby/directory

to the corresponding server section of pgmoneta.conf. [pgmoneta][pgmoneta] will create the directory if it doesn't exist, and keep the latest backup in the defined directory.

You can also configure muptiple hot standby directories (up to 8) by providing comma-separated paths:

/path/to/hot/standby1,/path/to/hot/standby2,/path/to/hot/standby3

[pgmoneta][pgmoneta] will maintain identical copies of the hot standby in all specified directories.

You can use

hot_standby_overrides = /your/local/hot/standby/overrides/

to override files in the hot_standby directories. The overrides will be applied to all hot_standby directories.

Tablespaces ​

By default tablespaces will be mapped to a similar path than the original one, for example /tmp/mytblspc becomes /tmp/mytblspchs.

However, you can use the directory name to map it to another directory, like

hot_standby_tablespaces = /tmp/mytblspc->/tmp/mybcktblspc

You can also use the OID for the key part, like

hot_standby_tablespaces = 16392->/tmp/mybcktblspc

Multiple tablespaces can be specified using a , between them.