Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller
Date
Msg-id dcc563d10902041336u3ae67abpedb8639425385346@mail.gmail.com
Whole thread Raw
In response to Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller  (Arjen van der Meijden <acmmailing@tweakers.net>)
Responses Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller  (Gregory Stark <stark@enterprisedb.com>)
Re: suggestions for postgresql setup on Dell 2950 , PERC6i controller  (Arjen van der Meijden <acmmailing@tweakers.net>)
List pgsql-performance
On Wed, Feb 4, 2009 at 2:11 PM, Arjen van der Meijden
<acmmailing@tweakers.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).

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