User-Agent: Microsoft-Entourage/11.3.3.061214
Date: Tue, 29 May 2007 14:50:57 -0700
Subject: Re: setting up raid10 with more than 4 drives
From: "Luke Lonergan" <llonergan@greenplum.com>
To: "Rajesh Kumar Mallah" <mallah.rajesh@gmail.com>,
	pgsql-performance@postgresql.org
Message-ID: <C281EE51.31A7F%llonergan@greenplum.com>
Thread-Topic: [PERFORM] setting up raid10 with more than 4 drives
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Stripe of mirrors is preferred to mirror of stripes for the best balance of
protection and performance.

In the stripe of mirrors you can lose up to half of the disks and still be
operational.  In the mirror of stripes, the most you could lose is two
drives.  The performance of the two should be similar - perhaps the seek
performance would be different for high concurrent use in PG.

- Luke


On 5/29/07 2:14 PM, "Rajesh Kumar Mallah" <mallah.rajesh@gmail.com> wrote:

> hi,
> 
> this is not really postgresql specific, but any help is appreciated.
> i have read more spindles the better it is for IO performance.
> 
> suppose i have 8 drives , should a stripe (raid0) be created on
> 2 mirrors (raid1) of 4 drives each OR  should a stripe on 4 mirrors
> of 2 drives each be created  ?
> 
> also does single channel  or dual channel controllers makes lot
> of difference in raid10 performance ?
> 
> regds
> mallah.
> 
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