From: Scott Marlowe <smarlowe@g2switchworks.com>
To: Alex Turner <armtuk@gmail.com>
Cc: Luke Lonergan <llonergan@greenplum.com>
Cc: Mikael Carneholm <Mikael.Carneholm@wirelesscar.com>
Cc: Ron Peacetree <rjpeace@earthlink.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: RAID stripe size question
Date: Tue, 18 Jul 2006 14:37:27 -0500
Message-ID: <1153251447.2744.73.camel@state.g2switchworks.com> (raw)
In-Reply-To: <33c6269f0607181227g7c6eea1av5b8dbd9787bfd1c7@mail.gmail.com>
References: <7F10D26ECFA1FB458B89C5B4B0D72C2B4E4C31@sesrv12.wirelesscar.com>
<C0E27CFD.2A4AC%llonergan@greenplum.com>
<33c6269f0607181227g7c6eea1av5b8dbd9787bfd1c7@mail.gmail.com>
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: smarlowe@g2switchworks.com, armtuk@gmail.com, llonergan@greenplum.com, Mikael.Carneholm@wirelesscar.com, rjpeace@earthlink.net
Subject: Re: RAID stripe size question
In-Reply-To: <1153251447.2744.73.camel@state.g2switchworks.com>
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