Re: Autodetect of software RAID1+0 fails

From: "Luke Lonergan" <llonergan(at)greenplum(dot)com>
To: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>, "Craig James" <craig_james(at)emolecules(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Autodetect of software RAID1+0 fails
Date: 2007-06-02 05:41:07
Message-ID: C2865103.322BB%llonergan@greenplum.com
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Steinar,

On 6/1/07 2:35 PM, "Steinar H. Gunderson" <sgunderson(at)bigfoot(dot)com> wrote:

> Either do your md discovery in userspace via mdadm (your distribution can
> probably help you with this), or simply use the raid10 module instead of
> building raid1+0 yourself.

I found md raid10 to be *very* slow compared to raid1+0 on Linux 2.6.9 ->
2.6.18. Very slow in this case is < 400 MB/s compared to 1,800 MB/s.

- Luke

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