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

On Wed, Feb 4, 2009 at 2:11 PM, Arjen van der Meijden
<acmmailing(at)tweakers(dot)net> wrote:
> On 4-2-2009 21:09 Scott Marlowe wrote:
>>
>> I have little experience with the 6i. I do have experience with all
>> the Percs from the 3i/3c series to the 5e series. My experience has
>> taught me that a brand new, latest model $700 Dell RAID controller is
>> about as good as a $150 LSI, Areca, or Escalade/3Ware controller.
>> I.e. a four or five year old design. And that's being generous.
>
> Afaik the Perc 5/i and /e are more or less rebranded LSI-cards (they're not
> identical in layout etc), so it would be a bit weird if they performed much
> less than the similar LSI's wouldn't you think?
> And as far as I can remember, our Perc 5/e actually performed similar to a
> LSI with similar specs (external sas, 256MB ram, etc) we had at the time of
> testing.
> Areca may be the fastest around right now, but if you'd like to get it all
> from one supplier, its not too bad to be stuck with Dell's perc 5 or 6
> series.

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).