From: Greg Smith <greg@2ndquadrant.com>
To: sergey <sergey.on.net@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: choosing the right RAID level for PostgresQL database
Date: Sun, 13 Feb 2011 18:23:19 -0500
Message-ID: <4D5867E7.1090409@2ndquadrant.com> (raw)
In-Reply-To: <AANLkTi=kYyOq-Y=pLaRSSLHg1vNZrjQ7HEr=PDs=yROb@mail.gmail.com>
References: <AANLkTi=kYyOq-Y=pLaRSSLHg1vNZrjQ7HEr=PDs=yROb@mail.gmail.com>
sergey wrote:
> I got a disk array appliance of 8 disks 1T each (UltraStor RS8IP4). It
> will be used solely by PostgresQL database and I am trying to choose
> the best RAID level for it.
> ..
> Space is the least important factor. Even 1T will be enough.
Use RAID10, measure the speed of the whole array using the bonnie++ ZCAV
tool, and only use the fastest part of each array to store the important
stuff. You will improve worst-case performance in both sequential reads
and seek time that way. Drives are nearly twice as fast at their
beginning as they are at the end, and with only 8 drives you should be
able to setup a RAID10 array with all the fast parts aligned.
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, sergey.on.net@gmail.com
Subject: Re: choosing the right RAID level for PostgresQL database
In-Reply-To: <4D5867E7.1090409@2ndquadrant.com>
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