Re: Archive Command Configuration

On Thu, Mar 23, 2006 at 12:28:41PM -0800, Steve Crawford wrote:
> >...I have a
> >cron job from the production database that runs every 5-10min to check
> >if there are any new archive logs and copy new archive logs to the
> >remote stand by failover machine.
> >
> >The problem with this scenario is that there might be a possibility that
> >I might scp a partially filled archive log over to the remote machine on
> >a heavily updated databases with batch jobs runnings most of the time
> >like ours.
> >
> > So, inorder to over come this we want to change the archive_command to
> >
> >archive_command = 'cp %p /archives-temp/%f && mv /archives-temp/%f
> >/archives/%f'
> >( I could do remote copy also with the command but I dont want to go
> >that route because of network problems. )
> >
> >....
> >
> > My question is there any problem in using this approach ? will I run
> >into problems in the future ? are there any other better ways of solving
> >this problem ?
>
> Looks like it should work but have you considered using rsync instead?
> If the file grows from one pass to the next, rsync will send the
> differences.

rsync does nothing to address the race condition issue, though. If you
fire up an rsync and the cp takes too long, you'll end up syncing a
partially written WAL file, which could potentially be bad.

BTW, there's also now a project on pgFoundry for using PITR to keep a
warm-backup: http://pgfoundry.org/projects/pgpitrha/
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461