Looking at the numbers, the raptor with TCQ enabled was close or beat
the Atlas III 10k drive on most benchmarks.

Naturaly a 15k drive is going to be faster in many areas, but it is
also much more expensive.  It was only 44% better on the server tests
than the raptor with TCQ, but it costs nearly 300% more ($538 cdw.com,
$180 newegg.com).  Note also that the 15k drive was the only drive
that kept up with the raptor on raw transfer speed, which is going to
matter for WAL.

For those of us on a budget, a quality controller card with lots of
RAM is going to be our biggest friend because it can cache writes, and
improve performance.  The 3ware controllers seem to be universally
benchmarked as the best SATA RAID 10 controllers where database
performance is concerned.  Even the crappy tweakers.net review had the
3ware as the fastest controller for a MySQL data partition in RAID 10.

The Raptor drives can be had for as little as $180/ea, which is quite
a good price point considering they can keep up with their SCSI 10k
RPM counterparts on almost all tests with NCQ enabled (Note that 3ware
controllers _don't_ support NCQ, although they claim their HBA based
queueing is 95% as good as NCQ on the drive).

Alex Turner

On 4/14/05, Dave Held <[EMAIL PROTECTED]> wrote:
> > -----Original Message-----
> > From: Alex Turner [mailto:[EMAIL PROTECTED]
> > Sent: Thursday, April 14, 2005 12:14 PM
> > Cc: Greg Stark; pgsql-performance@postgresql.org;
> > Subject: Re: [PERFORM] Intel SRCS16 SATA raid?
> >
> >
> > I have put together a little head to head performance of a 15k SCSI,
> > 10k SCSI 10K SATA w/TCQ, 10K SATA wo/TCQ and 7.2K SATA drive
> > comparison at storage review
> >
> > http://www.storagereview.com/php/benchmark/compare_rtg_2001.ph
> > p?typeID=10&testbedID=3&osID=4&raidconfigID=1&numDrives=1&devI
> > D_0=232&devID_1=40&devID_2=259&devID_3=267&devID_4=261&devID_5
> > =248&devCnt=6
> >
> > It does illustrate some of the weaknesses of SATA drives, but all in
> > all the Raptor drives put on a good show.
> > [...]
> I think it's a little misleading that your tests show 0ms seek times
> for some of the write tests.  The environmental test also selects a
> missing data point as the winner.  Besides that, it seems to me that
> seek time is one of the most important features for a DB server, which
> means that the SCSI drives are the clear winners and the non-WD SATA
> drives are the embarrassing losers.  Transfer rate is import, but
> perhaps less so because DBs tend to read/write small blocks rather
> than large files.  On the server suite, which seems to me to be the
> most relevant for DBs, the Atlas 15k spanks the other drives by a
> fairly large margin (especially the lesser SATA drives).  When you
> ignore the "consumer app" benchmarks, I wouldn't be so confident in
> saying that the Raptors "put on a good show".
> __
> David B. Held
> Software Engineer/Array Services Group
> 200 14th Ave. East,  Sartell, MN 56377
> 320.534.3637 320.253.7800 800.752.8129
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