Greetings, * Paul Förster (paul.foerster@xxxxxxxxx) wrote: > > On 26. Jun, 2020, at 12:29, Magnus Hagander <magnus@xxxxxxxxxxxx> wrote: > > I believe NetApp does atomic snapshots across multiple volumes, if you have them in the same consistency group. (If you don't then you're definitely in for a world of pain if you ever have to restore) > > > > Snapshotting multiple volumes in a consistency group will set up a write fence across them, then snapshot, and AIUI guarantees correct write ordering. > > That's how I understood it too. But it will be difficult in our complex storage world to get the storage guys to create a consistency group. > > Also, what I'm looking for is a plugin that allows to, how Netapp call it, "quiece" the PostgreSQL cluster, i.e. does start/stop backup. Presumably they mean 'quiesce', except that that *isn't* what PG's start/stop backup calls do, and assuming that's what happens is quite wrong and could lead to issues. The PG start/stop backup calls do things like wait for a checkpoint to happen and track when that checkpoint was and return that info along with whatever the stopping point of the backup is- so that you can make sure that you have all of the WAL between those two points, and so you can create the backup_label file that's needed to indicate on restore that you're restoring from a backup and not just doing crash recovery. If it isn't an atomic snapshot across everything then start/stop calls have to be done as well as all that other fun stuff. > I don't really trust the community plugin as it is so old and I'm not sure it gets any more development attention. For example, what about the API change (exclusive vs. non-exclusive)? Does it use the new API? No clue. Thanks, Stephen
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