From: Greg Stark <gsstark@mit.edu>
To: PFC <lists@boutiquenumerique.com>
Cc: Joshua D. Drake <jd@commandprompt.com>
Cc: Dave Cramer <pg@fastcrypt.com>
Cc: Michael Ben-Nes <miki@canaan.co.il>
Cc: pgsql-performance@postgresql.org
Subject: Re: Advice on RAID card
Date: 25 Sep 2005 13:41:06 -0400
Message-ID: <873bntjb9p.fsf@stark.xeocode.com> (raw)
In-Reply-To: <op.sxn3v7a1th1vuj@localhost>
References: <IGEGINLEEDLANNHAAKCMOECJCCAA.gaulakh@ecmarket.com>
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<43367937.40809@canaan.co.il>
<ABE6B997-2C1E-43B1-9F18-28F54B1620FE@fastcrypt.com>
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<op.sxn3v7a1th1vuj@localhost>
PFC <lists@boutiquenumerique.com> writes:
> Which makes me think that I will use Software Raid 5 and convert the
> price of the card into RAM.
> This should be nice for a budget server.
> Gonna investigate now if Linux software RAID5 is rugged enough. Can
> always buy the a card later if not.
Raid 5 is perhaps the exception here. For Raid 5 a substantial amount of CPU
power is needed.
Also, Raid 5 is particularly inappropriate for write-heavy Database traffic.
Raid 5 actually hurts write latency dramatically and Databases are very
sensitive to latency.
On the other hand if your database is primarily read-only then Raid 5 may not
be a problem and may be faster than raid 1+0.
--
greg
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To: pgsql-performance@postgresql.org
Cc: gsstark@mit.edu, lists@boutiquenumerique.com, jd@commandprompt.com, pg@fastcrypt.com, miki@canaan.co.il
Subject: Re: Advice on RAID card
In-Reply-To: <873bntjb9p.fsf@stark.xeocode.com>
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