From: Scott Marlowe <scott.marlowe@gmail.com>
To: Henrik <henke@mac.se>
Cc: glynastill@yahoo.co.uk, "Greg Smith" <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Filesystem benchmarking for pg 8.3.3 server
Date: Mon, 11 Aug 2008 07:20:08 -0600
Message-ID: <dcc563d10808110620t460b7928hffc2e350f04b9c58@mail.gmail.com> (raw)
In-Reply-To: <D92E27B8-47BF-49FC-A917-947FB44858B9@mac.se>
References: <158561.15546.qm@web25808.mail.ukl.yahoo.com>
<D92E27B8-47BF-49FC-A917-947FB44858B9@mac.se>
On Mon, Aug 11, 2008 at 6:08 AM, Henrik <henke@mac.se> wrote:
> 11 aug 2008 kl. 12.35 skrev Glyn Astill:
>
>>>>
>>>>> It feels like there is something fishy going on.
>>>
>>> Maybe the RAID 10
>>>>>
>>>>> implementation on the PERC/6e is crap?
>>>>
>>
>> It's possible. We had a bunch of perc/5i SAS raid cards in our servers
>> that performed quite well in Raid 5 but were shite in Raid 10. I switched
>> them out for Adaptec 5808s and saw a massive improvement in Raid 10.
>
> I suspected that. Maybe I should just put the PERC/6 cards in JBOD mode and
> then make a RAID10 with linux software raid MD?
You can also try making mirror sets with the hardware RAID controller
and then doing SW RAID 0 on top of that. Since RAID0 requires little
or no CPU overhead, this is a good compromise because the OS has the
least work to do, and the RAID controller is doing what it's probably
pretty good at, mirror sets.
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To: pgsql-performance@postgresql.org
Cc: scott.marlowe@gmail.com, henke@mac.se, gsmith@gregsmith.com
Subject: Re: Filesystem benchmarking for pg 8.3.3 server
In-Reply-To: <dcc563d10808110620t460b7928hffc2e350f04b9c58@mail.gmail.com>
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