Received: from magus.postgresql.org (magus.postgresql.org [87.238.57.229]) by mail.postgresql.org (Postfix) with ESMTP id BE0C2DE314D for ; Tue, 3 Apr 2012 10:22:01 -0300 (ADT) Received: from [2001:1528:137::f1] (helo=mail.gransy.com) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1SF3gL-0007B4-HV for pgsql-performance@postgresql.org; Tue, 03 Apr 2012 13:21:59 +0000 Received: from antispam.gransy.com (antispam.gransy.com [77.78.104.124]) by mail.gransy.com (Postfix) with ESMTP id 6421C508887 for ; Tue, 3 Apr 2012 15:21:42 +0200 (CEST) Received: from mail.gransy.com ([82.208.29.194]) by antispam.gransy.com (antispam.gransy.com [77.78.104.124]) (amavisd-new, port 10024) with ESMTP id wMBZQnDoL1hm for ; Tue, 3 Apr 2012 15:21:42 +0200 (CEST) Received: by mail.gransy.com (Postfix, from userid 5000) id 4F272508899; Tue, 3 Apr 2012 15:21:42 +0200 (CEST) Received: from [192.168.1.237] (ip-78-45-133-255.net.upcbroadband.cz [78.45.133.255]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.gransy.com (Postfix) with ESMTPSA id 25D7E508887 for ; Tue, 3 Apr 2012 15:21:42 +0200 (CEST) Message-ID: <4F7AF966.20809@fuzzy.cz> Date: Tue, 03 Apr 2012 15:21:42 +0200 From: Tomas Vondra User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120312 Thunderbird/11.0 MIME-Version: 1.0 To: pgsql-performance@postgresql.org Subject: Re: H800 + md1200 Performance problem References: <920BB532-C321-45A3-851E-8B688A5963F7@yahoo.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 2001:1528:137::f1 (failed) X-Pg-Spam-Score: -1.1 (-) X-Archive-Number: 201204/15 X-Sequence-Number: 46661 On 3.4.2012 14:59, Cesar Martin wrote: > Hi Mike, > Thank you for your fast response. > > blockdev --getra /dev/sdc > 256 That's way too low. Is this setting the same on both machines? Anyway, set it to 4096, 8192 or even 16384 and check the difference. BTW explain analyze is nice, but it's only half the info, especially when the issue is outside PostgreSQL (hw, OS, ...). Please, provide samples from iostat / vmstat or tools like that. Tomas