Thanks for the clarifications guys! Il giorno mar 27 apr 2021 alle ore 18:24 Jehan-Guillaume de Rorthais < j...@dalibo.com> ha scritto:
> On Mon, 26 Apr 2021 18:04:41 +0000 (UTC) > Strahil Nikolov <hunter86...@yahoo.com> wrote: > > > I prefer that the stack is auto enabled. Imagine that you got a DB that > is > > replicated and primary DB node is fenced. You would like that node to > join > > the cluster and if possible to sync with the new primary instead of > staying > > down. > > In the case of PostgreSQL, the failing primary may not be able to failback > automatically with the new primary. Worse, if it actually enters in > replication, it might just silently become a corrupted standby, giving a > wrong > feeling of safety, until a new failover occurs. > > PAF doesn't handle auto-failback (eg. pg_rewind) per design, to avoid code > complexity. We don't want to give a wrong feeling of perfect > full-availability/failback/fully-automated-admin'ed PgSQL cluster. If > something > went wrong with your DB, you better need to check and fix it. You need both > system and DBA guy on board to take care of the availability and safety of > your > cluster. > > Note that auto-failback of secondary nodes is safe, as far as they are able > to actually follow up with the production. Maybe we can imaginer some > safety > belts in PAF's code to allow Pacemaker auto-start on boot, but refuse > to start a badly shaped PostgreSQL. > > > One such example is the SAP HANA DB. Imagine that the current primary > > node looses storage and it failed to commit all transactions to disk. > Without > > replication you will endure data loss for the last 1-2 minutes (depends > on > > your monitoring interval) unless you got a replication. > > PAF is a shared-nothing approach, it requires replication between nodes. > > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ >
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