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 B41089DCCA5 for ; Wed, 15 Mar 2006 16:43:14 -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 31992-03 for ; Wed, 15 Mar 2006 16:43:15 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from gwmta.wicourts.gov (gwmta.wicourts.gov [165.219.244.99]) by postgresql.org (Postfix) with ESMTP id 46C479DC9AC for ; Wed, 15 Mar 2006 16:43:09 -0400 (AST) Received: from Courts-MTA by gwmta.wicourts.gov with Novell_GroupWise; Wed, 15 Mar 2006 14:43:11 -0600 Message-Id: <441827F5.EE98.0025.0@wicourts.gov> X-Mailer: Novell GroupWise Internet Agent 7.0 Date: Wed, 15 Mar 2006 14:43:01 -0600 From: "Kevin Grittner" To: "Joshua Drake" , Subject: Re: Background writer configuration References: <44181A11.EE98.0025.0@wicourts.gov> <200603151154.33504.jd@commandprompt.com> In-Reply-To: <200603151154.33504.jd@commandprompt.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.102 required=5 tests=[AWL=0.102] X-Spam-Score: 0.102 X-Spam-Level: X-Archive-Number: 200603/219 X-Sequence-Number: 17656 >>> On Wed, Mar 15, 2006 at 1:54 pm, in message <200603151154.33504.jd@commandprompt.com>, "Joshua D. Drake" wrote: >> I then did some calculations, based on the sustained write speed of our >> drive array (as measured by copying big files to it), and we tried >> this: >> >> bgwriter_lru_percent = 20.0 >> bgwriter_lru_maxpages = 200 >> bgwriter_all_percent = 10.0 >> bgwriter_all_maxpages = 600 >> >> This almost totally eliminated the clusters of timeouts, and caused the >> transaction application rate to increase by a factor of eight over the >> already- improved speed. (That is, we were running 30 to 35 times as >> many transactions per minute into the database, compared to the default >> background writer configuration.) I'm going to let these settings >> settle in for a week or two before we try adjusting them further (to see >> if we can eliminate those last few timeouts of this type). > > > Can you tell us what type of array you have? Each machine has a RAID5 array of 13 (plus one hot spare) 15,000 RPM Ultra 320 SCSI drives 2 machines using IBM ServRaid6M battery backed caching controllers 2 machines using IBM ServRaid4MX battery backed caching controllers