From: Jim C. Nasby <jnasby@pervasive.com>
To: pgsql-performance@postgresql.org
Subject: Re: SAN/NAS options
Date: Fri, 16 Dec 2005 18:25:25 -0600
Message-ID: <20051217002525.GC53809@pervasive.com> (raw)
In-Reply-To: <20051216225103.GE2883@mathom.us>
References: <Pine.OSX.4.61.0512140155590.282@office-dhcp-18.bway.net>
<439FC9B8.8020709@paradise.net.nz>
<20051216221801.GT53809@pervasive.com>
<20051216225103.GE2883@mathom.us>
On Fri, Dec 16, 2005 at 05:51:03PM -0500, Michael Stone wrote:
> On Fri, Dec 16, 2005 at 04:18:01PM -0600, Jim C. Nasby wrote:
> >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.
>
> The overhead of reading an 8k block instead of a 32k block is too small
> to measure on modern hardware. The seek is what dominates; leaving the
> read head on a little longer and then transmitting a little more over a
> 200 megabyte channel is statistical fuzz.
True, but now you've got 4x the amount of data in your cache that you
probably don't need.
Looks like time to do some benchmarking...
--
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
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com
Subject: Re: SAN/NAS options
In-Reply-To: <20051217002525.GC53809@pervasive.com>
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