Thanks for the response. I am using Postgresql 11. I want something simple and I have a strong preference toward using stock tools. After the promotion and the original master comes online, I was thinking of doing a pg_basebackup to sync. Any thoughts about that? I had a very hard time with pg_rewind and I didn't like its complexity.
On Wed, Jan 8, 2020 at 11:31 PM Michael Paquier <mich...@paquier.xyz> wrote: > On Wed, Jan 08, 2020 at 11:06:28PM -0500, Rita wrote: > > I run a master and standby setup with Postgresql 11. The systems are > > identical from a hardware and software setup. If the master goes down I > > can do a pg_ctl promote on the standby and point my applications to use > the > > standby (new master). > > > > Once the original master is online, when is an appropriate time to fail > > back over? And are there any other things besides promote after the > > failover is done? > > Make sure that you still have an HA configuration able to handle > multiple degrees of failures with always standbys available after a > promotion. > > The options available to rebuild your HA configuration after a > failover depend on the version of PostgreSQL you are using. After a > failover the most simple solution would be to always recreate a new > standby from a base backup taken from the freshly-promoted primary, > though it can be costly depending on your instance. You could also > use pg_rewind (available in core since 9.5) to recycle the previous > primary and reuse it as a standby of the new promoted custer. Note > that there are community-based solutions for such things, like > pg_auto_failover or pacemaker-based stuff just to name two. These > rely on more complex architectures, where a third node is present to > monitor the others (any sane HA infra ought to do at least that to be > honest). > -- > Michael > -- --- Get your facts first, then you can distort them as you please.--
