From: Jim C. Nasby <jnasby@pervasive.com>
To: Mark Kirkwood <markir@paradise.net.nz>
Cc: Charles Sprickman <spork@bway.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: SAN/NAS options
Date: Fri, 16 Dec 2005 16:18:01 -0600
Message-ID: <20051216221801.GT53809@pervasive.com> (raw)
In-Reply-To: <439FC9B8.8020709@paradise.net.nz>
References: <Pine.OSX.4.61.0512140155590.282@office-dhcp-18.bway.net>
<439FC9B8.8020709@paradise.net.nz>
On Wed, Dec 14, 2005 at 08:28:56PM +1300, Mark Kirkwood wrote:
> Another interesting thing to try is rebuilding the database ufs
> filesystem(s) with 32K blocks and 4K frags (as opposed to 8K/1K or
> 16K/2K - can't recall the default on 4.x). I found this to give a factor
> of 2 speedup on random disk access (specifically queries doing indexed
> joins).
Even if you're doing a lot of random IO? I would think that random IO
would perform better if you use smaller (8K) blocks, since there's less
data being read in and then just thrown away that way.
> Is it mainly your 2 disk machines that are IOPS bound? if so, a cheap
> option may be to buy 2 more cheetahs for them! If it's the 4's, well how
> about a 2U U320 diskpack from whomever supplies you the Supermicro boxes?
Also, on the 4 drive machines if you can spare the room you might see a
big gain by putting the tables on one mirror and the OS and transaction
logs on the other.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, markir@paradise.net.nz, spork@bway.net
Subject: Re: SAN/NAS options
In-Reply-To: <20051216221801.GT53809@pervasive.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox