Re: File system snapshots for multiple file systems

tomas(at)tuxteam(dot)de wrote:
> Checkpoinitng is definitely coolest. If your file system doesn't do
> that, rsync is a good poor man's replacement:
>
> first rsync (takes long)
> (or work from an older backup)
> pg_start_backup(...)
> rsync (should be much faster)
> rsync WAL
> pg_stop_backup()
>
> I regularly rsync moderately active 500GB filesystems on fairly feeble
> hardware in about 5-10 minutes (for daily backups).

That will *not* get you a consistent, safe backup. If a PostgreSQL
checkpoint happens while you're rsyncing the WAL, the data files won't
(necessarily) contain updates that were made between the rsync of the
data finished and the checkpoint.

To do that, you'd need to set up continuous archiving, and do a PITR
restore.

What I was complaining/suggesting is that we should make what you did to
actually work, because it's a lot simpler. And as Jonah pointed out,
we'd need to inhibit checkpoints between pg_start_backup() and
pg_stop_backup() to make it work.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com