From: Michael Monnerie <michael.monnerie@it-management.at>
To: Johann Spies <jspies@sun.ac.za>
To: pgsql-admin@postgresql.org
Subject: Re: Handling large volumes of data
Date: Tue, 8 Apr 2008 21:24:07 +0200
Message-ID: <200804082124.07687@zmi.at> (raw)
In-Reply-To: <20080408101336.GJ13409@sun.ac.za>
References: <20080408094233.GG13409@sun.ac.za>
<200804081201.15175@zmi.at>
<20080408101336.GJ13409@sun.ac.za>
On Dienstag, 8. April 2008 Johann Spies wrote:
> I have got 8x720G disks in a hardware raid 5 setup. It is a Dell 2950
> server. I am using an XFS-filesystem. I am not certain about the
> speed of the hard disk, but we bought the fastest we could get.
720G looks like SATA disks, probably with "only" 7.200rpm. The Western
Digital Raptor with 10.000rpm are about twice as fast on random access.
Also, RAID5/6 are very,very slow when it comes to small disk *writes*.
Which is exactly what a db makes. Retry with RAID-10, and you'll see
the difference.
We've had 6 WD Raptors in RAID-6 on an Areca RAID, and changed it to 8x
Raptor RAID-10, that improved things.
mfg zmi
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To: pgsql-admin@postgresql.org
Cc: michael.monnerie@it-management.at, jspies@sun.ac.za
Subject: Re: Handling large volumes of data
In-Reply-To: <200804082124.07687@zmi.at>
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