Re: Ideal hardware configuration for pgsql - Mailing list pgsql-general

> > A note about SCSI vs IDE... I have recently tried both on a dual
P3 with
> > 1gb of ram running Mandrake 7.2. I was amazed the idle CPU's were
> > running near 20-23% with nothing other then a bash shell running
on 2
> > IBM IDE ATA 100 drives. I converted to 2 IBM SCSI U2 drives and
the idle
> > CPU's went down to 0-2%. This was a tremendous difference. I feel
SCSI
> > is a must.

I have a suspicion that you didn't try using hdparm first to tune up
your disks. Have you set them up with 32-bit transfers, UDMA, and
unmasked interrupts? I am running a single 40 GB Maxtor 5400 UDMA/66
disk, and even when I am stress testing the database, about 96% on
each CPU goes to user-space postmaster processes. The system CPU
consumption rarely goes above 4%. And FYI, I am running a dual 1 GHz
P3 on a VP6. The IDE disk is connected to thepromise controller. I
haven't tried it on the VIA, but I suspect the results would be the
same. The only way I can see your CPU consumption going to 20% is if
you are using PIO, and haven't tuned up your disks.

> > I would like to try one of those new Promise Supertrak ATA 100
RAID 5
> > cards or hear from someone who has tried one... Anyone? I read
they have
> > the same onboard CPU as the Adaptec ultra160 RAID 5 card and can
have up
> > to twice as much onboard cache (128mb) as the SCSI counterpart. It
is
> > true hardware level raid 5 with a hot spare and each of the up to
6
> > drives is on its own interface. I would think this would alleviate
the
> > onboard IDE / CPU burn and improve the IDE performance
tremendously.
> >
> > The cost of the Promise Supertrak is over $100 more than the
Adaptec
> > ultra 160 card, but the ATA 100 drives are very inexpensive
compared to
> > SCSI. I found that you could get more than 4x the space for 25%
less
> > money with IDE ATA 100 RAID 5.
> >
> > If this is true... IDE RAID 5 might be a good alternative to SCSI.

UDMA without raid is already a good alternative to SCSI.

> > As for the Intel vs Sparc, well I use both. The Intel's are great
when
> > you need Windows but when you need performance the Intel just
can't keep
> > up with the stability, raw power or speed of Solaris 8 on a Sun
machine.

I'd dispute that. Admittedly, I haven't used the latest and greatest
in Sun hardware due to cost issues, but my experience says that
Linux+Intel is pretty much as good as SPARC+Solaris as far as
stability goes. I suppose for heavy number crunching, the late
UltraSPARC CPUs are much better, and Sun systems to generally feel
more responsive than standard PCs. It all depends on how much you want
to spend, and what sort of performance are you after.

> > As for the cost, we use HP dual 700 CPU x86 Netservers which cost
about
> > $30,000ea and with the Sun Developer program we saved 40% on our
Sun
> > machines which put the Sun E220 dual CPU in the same ballpark only
it
> > will run circles around the HP and I think anyone who develops
with Java
> > can become a Sun Developer.

$30,000 each??? And it is only a dual 700 P3? You are joking right? I
have just built a dual 1 GHz P3 server with 1 GB of PC133 CAS2, and
everything else for signifficantly less than $1,500! Where did the
remaining $28,500 go? 4 TB hardware RAID5 disk array with 1 GB of
cache and 10 hot spare disks? Because that would cost you roughly
$28K...

Regards.

Gordan