Re: Really bad diskio

On Fri, 2005-07-15 at 15:04 -0600, Ron Wills wrote:
> At Fri, 15 Jul 2005 13:45:07 -0700,
> Joshua D. Drake wrote:
> >
> > Ron Wills wrote:
> > > Hello all
> > >
> > >   I'm running a postgres 7.4.5, on a dual 2.4Ghz Athlon, 1Gig RAM and
> > > an 3Ware SATA raid.
> >
> > 2 drives?
> > 4 drives?
> > 8 drives?
>
>   3 drives raid 5. I don't believe it's the raid. I've tested this by
> moving the database to the mirrors software raid where the root is
> found and onto the the SATA raid. Neither relieved the IO problems.

Hard or soft RAID?  Which controller?  Many of the 3Ware controllers
(85xx and 95xx) have extremely bad RAID 5 performance.

Did you take any pgbench or other benchmark figures before you started
using the DB?

-jwb