X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id EEB71D8633 for ; Tue, 30 Aug 2005 15:28:48 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 29130-06 for ; Tue, 30 Aug 2005 18:28:44 +0000 (GMT) Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by svr1.postgresql.org (Postfix) with ESMTP id DC68FD85A0 for ; Tue, 30 Aug 2005 15:28:43 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [64.81.245.111] (account josh@agliodbs.com HELO temoku.sf.agliodbs.com) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 7995263; Tue, 30 Aug 2005 11:31:01 -0700 From: Josh Berkus Reply-To: josh@agliodbs.com Organization: Aglio Database Solutions To: pgsql-performance@postgresql.org Subject: Re: High load and iowait but no disk access Date: Tue, 30 Aug 2005 11:32:06 -0700 User-Agent: KMail/1.8 Cc: =?utf-8?q?R=C3=A9my_Beaumont?= References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508301132.06904.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.048 required=5 tests=[AWL=-0.002, FORGED_RCVD_HELO=0.05] X-Spam-Level: X-Archive-Number: 200508/532 X-Sequence-Number: 14279 Remy, > The behavior we see is that when running queries that do random reads > on disk, IOWAIT goes over 80% and actual disk IO falls to a crawl at a > throughput bellow 3000kB/s (We usually average 40000 kB/s to 80000 kB/s > on sequential read operations on the netapps) This seems pretty low for a NetApp -- you should be able to manage up to 180mb/s, if not higher. Are you sure it's configured correctly? -- --Josh Josh Berkus Aglio Database Solutions San Francisco