Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 249C69F992C for ; Wed, 22 Aug 2007 13:01:43 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 30454-02 for ; Wed, 22 Aug 2007 13:01:40 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from lists.commandprompt.com (host-254.commandprompt.net [207.173.203.254]) by postgresql.org (Postfix) with ESMTP id 0371E9F9868 for ; Wed, 22 Aug 2007 13:01:39 -0300 (ADT) Received: from [192.168.1.50] (or-67-76-146-141.sta.embarqhsd.net [67.76.146.141]) (authenticated bits=0) by lists.commandprompt.com (8.13.7/8.13.6) with ESMTP id l7MG1dPh019877 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 22 Aug 2007 09:01:40 -0700 Message-ID: <46CC5DE7.9010201@commandprompt.com> Date: Wed, 22 Aug 2007 09:01:43 -0700 From: "Joshua D. Drake" User-Agent: Thunderbird 1.5.0.12 (X11/20070604) MIME-Version: 1.0 To: Dmitry Potapov CC: pgsql-performance@postgresql.org Subject: Re: io storm on checkpoints, postgresql 8.2.4, linux References: <878c83960708220833l72dbd461k827aea77ec7d6c32@mail.gmail.com> In-Reply-To: <878c83960708220833l72dbd461k827aea77ec7d6c32@mail.gmail.com> X-Enigmail-Version: 0.94.2.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.91.1/4028/Wed Aug 22 03:18:18 2007 on projects.commandprompt.com X-Virus-Status: Clean X-Greylist: Sender succeded SMTP AUTH authentication, not delayed by milter-greylist-1.6 (lists.commandprompt.com [192.168.2.159]); Wed, 22 Aug 2007 09:01:40 -0700 (PDT) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200708/237 X-Sequence-Number: 26367 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dmitry Potapov wrote: > Hello! > > We run a large (~66Gb) web-backend database on Postgresql 8.2.4 on > Linux. The hardware is Dual Xeon 5130 with 16Gb ram, LSI Megaraid U320-2x > scsi controller w/512Mb writeback cache and a BBU. Storage setup contains 3 > raid10 arrays (data, xlog, indexes, each on different array), 12 HDDs total. > Frontend application uses jdbc driver, connection pooling and threads. > > We've run into an issue of IO storms on checkpoints. Once in 20min > (which is checkpoint_interval) the database becomes unresponsive for about > 4-8 seconds. Query processing is suspended, server does nothing but writing What are your background writer settings? Joshua D. Drake - -- === The PostgreSQL Company: Command Prompt, Inc. === Sales/Support: +1.503.667.4564 24x7/Emergency: +1.800.492.2240 PostgreSQL solutions since 1997 http://www.commandprompt.com/ UNIQUE NOT NULL Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate PostgreSQL Replication: http://www.commandprompt.com/products/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGzF3nATb/zqfZUUQRAsV8AJ9Sg7yTUfTGKTB/vQdW5BucwgcRSgCeKqIE jzR7X5+n0x1Y91etGOBvvpE= =4Dc9 -----END PGP SIGNATURE-----