Re: Experience with HP Smart Array P400 and SATA drives? - Mailing list pgsql-performance

From Mario Weilguni
Subject Re: Experience with HP Smart Array P400 and SATA drives?
Date
Msg-id 493E6023.3030800@sime.com
Whole thread Raw
In response to Re: Experience with HP Smart Array P400 and SATA drives?  ("Scott Marlowe" <scott.marlowe@gmail.com>)
Responses Re: Experience with HP Smart Array P400 and SATA drives?  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-performance
Scott Marlowe schrieb:
> On Tue, Dec 2, 2008 at 2:22 AM, Mario Weilguni <mweilguni@sime.com> wrote:
>
>> Has anyone benchmarked this controller (PCIe/4x, 512 MB BBC)? We try to use
>> it with 8x SATA 1TB drives in RAID-5 mode under Linux, and measure strange
>> values. An individual drive is capable of delivering 91 MB/sec sequential
>> read performance, and we get values ~102MB/sec out of a 8-drive RAID5, seems
>> to be ridiculous slow. Write performance seems to be much better, ~300 MB
>> /sec - seems ok to me.
>>
>> I guess I must be doing something wrong, I cannot believe that a 500 €
>> controller is delivering such poor performance.
>>
>
> A few suggestions...  Try to find the latest driver for your card, try
> using the card as nothing but a caching controller and run your RAID
> on software in linux (or whatever IS you're on).  Test a 2 drive
> RAID-0 to see what kind of performance increase you get.  If you can't
> dd a big file off of a RAID-0 at about 2x the rate of a single drive
> then something IS wrong with it. Try RAID 10.  Try RAID-1 sets on the
> controller and RAID 0 over that in software.
>
>

I've already tried Softraid with individual drives, performs much
better. However, it's no option to use softraid, so I'm stuck. The card
has the latest firmware installed, and there are no drivers needed,
they're already included in the linux kernel.

I still think we must be doing something wrong here, I googled the
controller and Linux, and did not find anything indicating a problem.
The HP SmartArray series is quite common, so a lot of users would have
the same problem.

Thanks!

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