Re: PostgreSQL: CPU utilization creeping to 100%

On 4/3/13, Eduardo Morras <emorrasg(at)yahoo(dot)es> wrote:
> a) Perhaps process are waiting to I/O, do you take zfs snapshots? How often?
> It can limit your i/o performance. Check the output of #zpool iostat 5
>
> b) Is the zpool ok? If one of the disks lags behind the others (because
> hardware errors) reconstructing the raidz should show what you say. Check
> the output of #zpool status when the "cpu storm" happens.
>
> c) If you do a simple #top -U postgres (or the user that executes your
> postgres server), what does the STATE column show? Check that to know the
> kernel state of the process.
>
> d) Do you use the standard values for zfs? Specially arc values.

Hmm, your points do make sense. Tuning postgresql.conf seems to have
done the trick for now, but if this issue pops up again I'll
definitely run through the diagnostics you have suggested.

Standard zfs arc values, yes.

Thanks,

-David