Re: Backup causing poor performance - suggestions

On Mon, May 5, 2008 at 10:11 AM, Campbell, Lance <lance(at)uiuc(dot)edu> wrote:
> Scott,
> The last 6 entries are when the system is not backing up. The system
> was running fine. But the other entries are when it was backing up.
> Reads seem to be fine but any operations that need to write data just
> hang.

Could you repost that as an attachment? the wrapping applied by your
email client makes it very hard to read.

Just perusing it, it doesn't look like you're CPU bound, but I/O bound.

As Craig mentioned, you may do better with some form of replication
solution here than pg_dumps.

Given that your db can fit in memory (when you say it's 8G do you mean
ON DISK, or in a backup? Big diff) then the only thing the backups
should be slowing down are update queries. Select queries shouldn't
even notice.

However, there's a LOT of wait state, and only blocks out, not really
many in, so I'm guessing that you've got a fair bit of writing going
on at the same time as your backups.