Stephen,
Our application don't write lot of data, so i don't think the time taken on replaying the WAL will be an issue for us. For reliability, as you said, i was thinking in running a large pgbench which writes a lot of data, while taking snapshots. Then my idea was to restart from snapshots and see if everything works as expected. I thought that based on the feedback from the community, maybe i wouldn't need to run these tests. Thank you. Cordialement, *Ghislain Rouvignac* Email : g...@sylob.com Bureau : + 33 (0)5 63 53 08 18 7, rue Marcel Dassault ZA de la Mouline 81990 Cambon d’Albi France Le dim. 28 oct. 2018 à 16:35, Stephen Frost <sfr...@snowman.net> a écrit : > Greetings, > > * Ghislain ROUVIGNAC (g...@sylob.com) wrote: > > Portworx says that on a running PostgreSQL it can: > > > > - replicate volumes for failover > > - take snapshots of volumes > > - backup volumes > > The downside with any snapshot-style approach is that it means that when > you have a failure, you have to go through and replay all the WAL since > the last checkpoint, which is single-threaded and can take a large > amount of time. > > This is why PostgreSQL has streaming replication, where we are > constantly sending WAL to the replica and replaying it immediately, and > that also allows us to have synchronous replication that is quorum based > and works with PostgreSQL, unlike what a snapshot level system would > provide. > > When doing your testing, I'd strongly recommend that you have a large > max_wal_size, run a large pgbench which writes a lot of data, and see > how long a failover takes with this system. > > > Does someone use them in production ? > > How reliable are these features ? > > Are there performance impacts of snapshots ? > > I don't know anything about the actual utilization of this in production > or if this implementation is reliable, just to be clear. My comments > specifically are about the performance of using a snapshot-based > approach (which could be this solution or various other ones). > > Thanks! > > Stephen > -- Notice de confidentialité : Les informations contenues dans ce courriel sont strictement confidentielles et réservées à l'usage de la ou des personne(s) identifiée(s) comme destinataire(s). L'usage, la publication, la copie, la divulgation ou la transmission des informations contenues dans ce message ou les documents qui y sont attachés est interdit à moins d'y avoir été expressément autorisé par l'émetteur. Si vous avez reçu ce message par erreur, merci de le supprimer et d'en avertir immédiatement son expéditeur.
