From: Ron Peacetree <rjpeace@earthlink.net>
To: Scott Marlowe <smarlowe@g2switchworks.com>
Cc: PG Performance <pgsql-performance@postgresql.org>
Subject: Re: RAID stripe size question
Date: Tue, 18 Jul 2006 15:43:29 -0400 (GMT-04:00)
Message-ID: <3595533.1153251809718.JavaMail.root@elwamui-huard.atl.sa.earthlink.net> (raw)
Have you done any experiments implementing RAID 50 this way (HBA does RAID 5, OS does RAID 0)? If so, what were the results?
Ron
-----Original Message-----
>From: Scott Marlowe <smarlowe@g2switchworks.com>
>Sent: Jul 18, 2006 3:37 PM
>To: Alex Turner <armtuk@gmail.com>
>Cc: Luke Lonergan <llonergan@greenplum.com>, Mikael Carneholm <Mikael.Carneholm@wirelesscar.com>, Ron Peacetree <rjpeace@earthlink.net>, pgsql-performance@postgresql.org
>Subject: Re: [PERFORM] RAID stripe size question
>
>On Tue, 2006-07-18 at 14:27, Alex Turner wrote:
>> This is a great testament to the fact that very often software RAID
>> will seriously outperform hardware RAID because the OS guys who
>> implemented it took the time to do it right, as compared with some
>> controller manufacturers who seem to think it's okay to provided
>> sub-standard performance.
>>
>> Based on the bonnie++ numbers comming back from your array, I would
>> also encourage you to evaluate software RAID, as you might see
>> significantly better performance as a result. RAID 10 is also a good
>> candidate as it's not so heavy on the cache and CPU as RAID 5.
>
>Also, consider testing a mix, where your hardware RAID controller does
>the mirroring and the OS stripes ((R)AID 0) over the top of it. I've
>gotten good performance from mediocre hardware cards doing this. It has
>the advantage of still being able to use the battery backed cache and
>its instant fsync while not relying on some cards that have issues
>layering RAID layers one atop the other.
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To: pgsql-performance@postgresql.org
Cc: rjpeace@earthlink.net, smarlowe@g2switchworks.com
Subject: Re: RAID stripe size question
In-Reply-To: <3595533.1153251809718.JavaMail.root@elwamui-huard.atl.sa.earthlink.net>
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