Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 528E72E00E7 for ; Fri, 14 Mar 2008 13:17:35 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 05286-03 for ; Fri, 14 Mar 2008 13:17:11 -0300 (ADT) X-Greylist: delayed 01:00:36.656796 by SQLgrey-1.7.5 Received: from vms042pub.verizon.net (vms042pub.verizon.net [206.46.252.42]) by postgresql.org (Postfix) with ESMTP id DB3CB2E0109 for ; Fri, 14 Mar 2008 13:17:11 -0300 (ADT) Received: from osgiliath.mathom.us ([72.83.241.121]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2-6.01 (built Apr 3 2006)) with ESMTPA id <0JXQ00DRZ7QTLCO7@vms042.mailsrvcs.net> for pgsql-performance@postgresql.org; Fri, 14 Mar 2008 10:16:06 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by osgiliath.mathom.us (Postfix) with ESMTP id 241AE70DCB; Fri, 14 Mar 2008 11:16:05 -0400 (EDT) Received: from osgiliath.mathom.us ([127.0.0.1]) by localhost (osgiliath.home.mathom.us [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Td3W45Urw8pq; Fri, 14 Mar 2008 11:16:03 -0400 (EDT) Received: by osgiliath.mathom.us (Postfix, from userid 1000) id 0496A71339; Fri, 14 Mar 2008 11:16:02 -0400 (EDT) Date: Fri, 14 Mar 2008 11:16:02 -0400 From: Michael Stone Subject: Re: Benchmark: Dell/Perc 6, 8 disk RAID 10 In-reply-to: To: Greg Smith Cc: pgsql-performance@postgresql.org Mail-followup-to: Greg Smith , pgsql-performance@postgresql.org Message-id: <20080314151600.GD2626@mathom.us> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-disposition: inline X-Virus-Scanned: Debian amavisd-new at mathom.us X-Pgp-Fingerprint: 53 FF 38 00 E7 DD 0A 9C 84 52 84 C5 EE DF 7C 88 References: <47D00DB2.7040007@emolecules.com> <18451.1204824562@sss.pgh.pa.us> <47D0AFC1.5070305@emolecules.com> <47D8B3B6.3010606@emolecules.com> <20080312225554.52f6275b@commandprompt.com> <47D9402A.3050903@emolecules.com> <20080313140618.3449ba58@commandprompt.com> User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200803/308 X-Sequence-Number: 29262 On Thu, Mar 13, 2008 at 05:27:09PM -0400, Greg Smith wrote: >I haven't found fdatasync to be significantly better in my tests on Linux >but I never went out of my way to try and quantify it. My understanding >is that some of the write barrier implementation details on ext3 >filesystems make any sync call a relatively heavy operation but I haven't >poked at the code yet to figure out why. Which is why having the checkpoints on a seperate ext2 partition tends to be a nice win. (Even if its not on a seperate disk.) Mike Stone