X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id E5C549DCB82 for ; Fri, 16 Dec 2005 18:18:03 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 60224-08 for ; Fri, 16 Dec 2005 18:18:03 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from flake.decibel.org (flake.decibel.org [67.100.216.10]) by postgresql.org (Postfix) with ESMTP id 9AC069DCAEF for ; Fri, 16 Dec 2005 18:17:59 -0400 (AST) Received: by flake.decibel.org (Postfix, from userid 1001) id B0BD71525C; Fri, 16 Dec 2005 16:18:01 -0600 (CST) Date: Fri, 16 Dec 2005 16:18:01 -0600 From: "Jim C. Nasby" To: Mark Kirkwood Cc: Charles Sprickman , pgsql-performance@postgresql.org Subject: Re: SAN/NAS options Message-ID: <20051216221801.GT53809@pervasive.com> References: <439FC9B8.8020709@paradise.net.nz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <439FC9B8.8020709@paradise.net.nz> X-Operating-System: FreeBSD 4.11-RELEASE-p10 i386 X-Distributed: Join the Effort! http://www.distributed.net User-Agent: Mutt/1.5.9i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.007 required=5 tests=[AWL=0.007] X-Spam-Score: 0.007 X-Spam-Level: X-Archive-Number: 200512/408 X-Sequence-Number: 16229 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