Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 214AF2E0175 for ; Sat, 1 Mar 2008 14:13:43 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 96796-01 for ; Sat, 1 Mar 2008 14:13:36 -0400 (AST) X-Greylist: delayed 00:06:40.013609 by SQLgrey-1.7.5 Received: from mail.emolecules.com (66-226-76-106.dedicated.abac.net [66.226.76.106]) by postgresql.org (Postfix) with ESMTP id 3FC762E0168 for ; Sat, 1 Mar 2008 14:13:37 -0400 (AST) Received: (qmail 737 invoked by uid 2020); 1 Mar 2008 10:06:55 -0800 Received: from wsip-68-224-174-233.sd.sd.cox.net (HELO lisa-james-computer.local) (68.224.174.233) by 192.168.0.4 with SMTP; 1 Mar 2008 10:06:55 -0800 Message-ID: <47C99B3E.4010606@emolecules.com> Date: Sat, 01 Mar 2008 10:06:54 -0800 From: Craig James User-Agent: Thunderbird 2.0.0.12 (Macintosh/20080213) MIME-Version: 1.0 To: pgsql-performance Subject: How to allocate 8 disks References: <1204285894.11773.33.camel@franck-gusty> <1204296705.11773.51.camel@franck-gusty> <47C88826.4040209@paradise.net.nz> In-Reply-To: <47C88826.4040209@paradise.net.nz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200803/5 X-Sequence-Number: 28959 We're upgrading to a medium-sized server, a Dell PowerEdge 2950, dual-quad CPU's and 8 GB memory. This box can hold at most 8 disks (10K SCSI 2.5" 146 GB drives) and has Dell's Perc 6/i RAID controller. I'm thinking of this: 6 disks RAID 1+0 Postgres data 1 disk WAL 1 disk Linux I've often seen RAID 1 recommended for the WAL. Is that strictly for reliability, or is there a performance advantage to RAID 1 for the WAL? It seems to me separating the OS and WAL on two disks is better than making a single RAID 1 and sharing it, from a performance point of view. Thanks, Craig