Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. It only takes a minute to sign up.
Sign up to join this community
I am reading tutorials on how to setup streaming replication in Postgres from master to slave.
Some tutorials recommend setting up archiving in the master (and restoring in slave) . In the master, this needs to be set in the conf file:
wal_level = hot_standby
archive_mode = on
archive_command = 'some rsync command to rsync logfile segments from master to slave'
What is the purpose of this archiving? When is it not necessary when setting up streaming replication?
WAL archiving is useful when you're running streaming replication, because there's a limit to how much WAL the master will retain.
If you don't archive WAL, and the replica gets s far behind that the master has discarded WAL it still needs, it cannot recover and must be replaced with a fresh base backup from the master.
It's also useful for PITR for disaster recovery purposes.
recovery.conf entry for the restore_command. The master may also need restarting to set an archive_command.
Feb 10, 2014 at 3:24