Re: Really bad diskio

At Fri, 15 Jul 2005 14:17:34 -0700,
Jeffrey W. Baker wrote:
>
> 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?

No, unfortunatly, I'm more or less just the developer for the
automation systems and admin the system to keep everything going. I
have very little say in the hardware used and I don't have any
physical access to the machine, it's found a province over :P.
But, for what the system, this IO seems unreasonable. I run
development on a 1.4Ghz Athlon, Gentoo system, with no raid and I
can't reproduce this kind of IO :(.

> -jwb