Re: PITR with rsync

On Mon, Aug 06, 2007 at 08:27:13PM -0400, Tom Lane wrote:
> David Bear <David(dot)Bear(at)asu(dot)edu> writes:
> > I'm still uncomfortable with using the file system style backup method
> > in PITR and am very interested in ' more information ' on how others
> > may be doing backups. Specifically, I assume that PITR methods would
> > also be accompanied with some combination of pg-dump.
>
> You assume wrong. Replaying WAL demands starting from a physical not
> logical dump, because page and tuple numbers and so forth have to be the
> same as in the master. A pg_dump backup will simply not work.
>
> > I am curious
> > about how frequently a pg-dump would be done if a PITR method was also
> > used (every 24 hours, every 7 days, not at all ) ??
>
> I'd personally be inclined to take a pg_dump every now and then just to
> have an independent backup method. Especially if I wasn't comfortable
> with PITR ;-). How often depends on how much bandwidth you can spare
> for backup purposes.

okay, thanks. the pg-dump is not an augementation, but a completely
separate backup method.

>
> > Also, looking at the archive_command argument in postgresql.conf. Has
> > anyone use rsync there?
>
> I suppose you could, but what's the point? Copying a single file that
> doesn't currently exist on the destination plays to none of rsync's
> strengths.

well, I was using rysnc so I could copy to a different computer over
ssh, not using the rsync protocol to catch diffs. I don't have a
remote file system mounted so I can do just a cp. Am I still thinking
wrong here?

>
> regards, tom lane

--
David Bear
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