On Jan 14, 2014 2:44 PM, "Andres Freund" <and...@2ndquadrant.com> wrote: > > On 2014-01-14 14:42:36 +0100, Magnus Hagander wrote: > > On Tue, Jan 14, 2014 at 2:41 PM, Andres Freund <and...@2ndquadrant.com >wrote: > > > > > On 2014-01-14 14:40:46 +0100, Magnus Hagander wrote: > > > > On Tue, Jan 14, 2014 at 2:18 PM, Andres Freund < and...@2ndquadrant.com > > > >wrote: > > > > > > > > > On 2014-01-14 14:12:46 +0100, Magnus Hagander wrote: > > > > > > Either way - if we can do this in a safe way, it sounds like a good > > > idea. > > > > > > It would be sort of like rsync, except relying on the fact that we > > > can > > > > > look > > > > > > at the LSN and don't have to compare the actual files, right? > > > > > > > > > > Which is an advantage, yes. On the other hand, it doesn't fix problems > > > > > with a subtly broken replica, e.g. after a bug in replay, or disk > > > > > corruption. > > > > > > > > > > > > > > Right. But neither does rsync, right? > > > > > > Hm? Rsync's really only safe with --checksum and with that it definitely > > > should fix those? > > > > > > > > I think we're talking about difference scenarios. > > Sounds like it. > > > I thought you were talking about a backup taken from a replica, that > > already has corruption. rsync checksums surely aren't going to help with > > that? > > I was talking about updating a standby using such an incremental or > differential backup from the primary (or a standby higher up in the > cascade). If your standby is corrupted in any way a rsync --checksum > will certainly correct errors if it syncs from a correct source?
Sure, but as I understand it that's not at all the scenario that the suggested functionality is for. You can still use rsync for that, I don't think anybody suggested removing that ability. Replicas weren't the target... /Magnus
