Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 609E39FA229 for ; Tue, 11 Sep 2007 21:10:58 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 23424-07-3 for ; Tue, 11 Sep 2007 21:10:44 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id 192039F9D78 for ; Tue, 11 Sep 2007 21:10:49 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l8C0AooT029200 for ; Tue, 11 Sep 2007 20:10:50 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l8C0Ao3J029197 for ; Tue, 11 Sep 2007 20:10:50 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Tue, 11 Sep 2007 20:10:50 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-performance@postgresql.org Subject: Re: random_page_costs - are defaults of 4.0 realistic for SCSI RAID 1 In-Reply-To: <87r6l4ajqh.fsf@oxford.xeocode.com> Message-ID: References: <87lkbdlkxw.fsf@oxford.xeocode.com> <46E676D6.70807@verizon.net> <87zlzt9ifw.fsf@oxford.xeocode.com> <46E6E338.5050403@verizon.net> <20070911213105.GF38801@decibel.org> <87r6l4ajqh.fsf@oxford.xeocode.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200709/212 X-Sequence-Number: 26757 On Wed, 12 Sep 2007, Gregory Stark wrote: > Also, it helps to run a "vmstat 1" in another window and watch the bi and bo > columns. Recently on Linux systems I've been using dstat ( http://dag.wieers.com/home-made/dstat/ ) for live monitoring in this sort of situation. Once you get the command line parameters right, you can get data for each of the major disks on your system that keep the columns human readable (like switching from KB/s to MB/s as appropriate) as activity goes up and down combined with the standard vmstat data. I still use vmstat/iostat if I want to archive or parse the data, but if I'm watching it I always use dstat now. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD