Re: Postgresql Performance on an HP DL385 and

Luke,

I check dmesg one more time and I found this regarding the cciss driver:

Filesystem "cciss/c1d0p1": Disabling barriers, not supported by the
underlying device.

Don't know if it means anything, but thought I'd mention it.

Steve

On 8/8/06, Steve Poe <steve(dot)poe(at)gmail(dot)com> wrote:
>
> Luke,
>
> I thought so. In my test, I tried to be fair/equal since my Sun box has
> two 4-disc arrays each on their own channel. So, I just used one of them
> which should be a little slower than the 6-disc with 192MB cache.
>
> Incidently, the two internal SCSI drives, which are on the 6i adapter,
> generated a TPS of 18.
>
> I thought this server would impressive from notes I've read in the group.
> This is why I thought I might be doing something wrong. I stumped which way
> to take this. There is no obvious fault but something isn't right.
>
> Steve
>
>
> On 8/8/06, Luke Lonergan <LLonergan(at)greenplum(dot)com> wrote:
> >
> > Steve,
> >
> > > Sun box with 4-disc array (4GB RAM. 4 167GB 10K SCSI RAID10
> > > LSI MegaRAID 128MB). This is after 8 runs.
> > >
> > > dbserver-dual-opteron-centos,08/08/06,Tuesday,20,us,12,2,5
> > > dbserver-dual-opteron-centos,08/08/06,Tuesday,20,sy,59,50,53
> > > dbserver-dual-opteron-centos,08/08/06,Tuesday,20,wa,1,0,0
> > > dbserver-dual-opteron-centos,08/08/06,Tuesday,20,id,45,26,38
> > >
> > > Average TPS is 75
> > >
> > > HP box with 8GB RAM. six disc array RAID10 on SmartArray 642
> > > with 192MB RAM. After 8 runs, I see:
> > >
> > > intown-vetstar-amd64,08/09/06,Tuesday,23,us,31,0,3
> > > intown-vetstar-amd64,08/09/06,Tuesday,23,sy,16,0,1
> > > intown-vetstar-amd64,08/09/06,Tuesday,23,wa,99,6,50
> > > intown-vetstar-amd64,08/09/06,Tuesday,23,id,78,0,42
> > >
> > > Average TPS is 31.
> >
> > Note that the I/O wait (wa) on the HP box high, low and average are all
> > *much* higher than on the Sun box. The average I/O wait was 50% of one
> > CPU, which is huge. By comparison there was virtually no I/O wait on
> > the Sun machine.
> >
> > This is indicating that your HP machine is indeed I/O bound and
> > furthermore is tying up a PG process waiting for the disk to return.
> >
> > - Luke
> >
> >
>