Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 4E53E9FA17A for ; Thu, 30 Nov 2006 22:24:49 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-new, port 10024) with ESMTP id 66519-10 for ; Thu, 30 Nov 2006 22:24:36 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from skunk.mtbrook.bozemanpass.com (skunk.mtbrook.bozemanpass.com [69.145.82.195]) by postgresql.org (Postfix) with ESMTP id B00B19FA282 for ; Thu, 30 Nov 2006 22:24:36 -0400 (AST) Received: from [69.145.82.218] (unknown [69.145.82.218]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by skunk.mtbrook.bozemanpass.com (Postfix) with ESMTP id 4EAC25582C5; Thu, 30 Nov 2006 18:24:34 -0800 (PST) Message-ID: <456F9262.4080207@boreham.org> Date: Thu, 30 Nov 2006 19:24:34 -0700 From: David Boreham Reply-To: david_list@boreham.org User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: carlos.reimer@opendb.com.br CC: pgsql-performance@postgresql.org Subject: Re: Bad iostat numbers References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200611/284 X-Sequence-Number: 22054 Carlos H. Reimer wrote: > > > avg-cpu: %user %nice %system %iowait %idle > > 50.40 0.00 0.50 1.10 48.00 > > > > Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s > avgrq-sz avgqu-sz await svctm %util > > sda 0.00 7.80 0.40 6.40 41.60 113.60 20.80 > 56.80 22.82 570697.50 10.59 147.06 100.00 > > sdb 0.20 7.80 0.60 6.40 40.00 113.60 20.00 > 56.80 21.94 570697.50 9.83 142.86 100.00 > > md1 0.00 0.00 1.20 13.40 81.60 107.20 40.80 > 53.60 12.93 0.00 0.00 0.00 0.00 > > md0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 > 0.00 0.00 0.00 0.00 0.00 0.00 > > > > Are they not saturated? > > > > What kind of parameters should I pay attention when comparing SCSI > controllers and disks? I would like to discover how much cache is > present in the controller, how can I find this value from Linux? > > These number look a bit strange. I am wondering if there is a hardware problem on one of the drives or on the controller. Check in syslog for messages about disk timeouts etc. 100% util but 6 writes/s is just wrong (unless the drive is a 1980's vintage floppy).