Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller

On 4-2-2009 22:36 Scott Marlowe wrote:
> We purhcased the Perc 5E, which dell wanted $728 for last fall with 8
> SATA disks in an MD-1000 and the performance is just terrible. No
> matter what we do the best throughput on any RAID setup was about 30
> megs/second write and 60 Megs/second read. I can get that from a
> mirror set of the same drives under linux kernel software RAID. This
> was with battery backed cache enabled. Could be an interaction issue
> with the MD-1000, or something, but the numbers are just awful. We
> have a Perc 6(i or e not sure) on a 6 disk SAS array and it's a little
> better, getting into the hundred meg/second range, but nothing
> spectacular. They're stable, which is more than I can say for a lot
> of older PERCs and the servers they came in (x600 series with Perc 3i
> for instance).

When we purchased our Perc 5/e with MD1000 filled with 15 15k rpm sas
disks, my colleague actually spend some time benchmarking the PERC and a
ICP Vortex (basically a overclocked Adaptec) on those drives.
Unfortunately he doesn't have too many comparable results, but it
basically boiled down to quite good scores for the PERC and a bit less
for the ICP Vortex.
IOMeter sequential reads are above 300MB/s for the RAID5 and above
240MB/s for a RAID10 (and winbench99 versions range from 400+ to
600+MB/s). The results for a 10, 12 and to 14 disk configuration also
showed nice increments in performance.

So we've based our purchase on my colleague's earlier bad experience
with Adaptec (much worse results than LSI) and weren't dissapointed by
Dell's scores. I have no idea whether Adaptec's results have increased
over time, unfortunately we haven't had a larger scale disk IO-benchmark
for quite some time.

If you're able to understand Dutch, you can click around here:
http://tweakers.net/benchdb/test/90

Best regards,

Arjen