Received: from localhost (unknown [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id 5ACB365015E for ; Thu, 11 Sep 2008 02:20:11 -0300 (ADT) Received: from postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 78984-03-2 for ; Thu, 11 Sep 2008 02:20:08 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from pih-relay06.plus.net (pih-relay06.plus.net [212.159.14.19]) by postgresql.org (Postfix) with ESMTP id DB315650172 for ; Thu, 11 Sep 2008 02:19:53 -0300 (ADT) Received: from [80.229.150.39] (helo=pd600.barnhouse) by pih-relay06.plus.net with esmtp (Exim) id 1Kdeao-0004wC-Kt; Thu, 11 Sep 2008 06:19:46 +0100 Received: from [192.168.0.87] (unknown [192.168.0.87]) by pd600.barnhouse (Postfix) with ESMTP id 65D2F4E1C25; Thu, 11 Sep 2008 06:25:35 +0100 (BST) Message-ID: <48C8AACD.5090702@mansionfamily.plus.com> Date: Thu, 11 Sep 2008 06:21:17 +0100 From: James Mansion Organization: MsgWare User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: Greg Smith CC: Scott Carey , Mark Wong , pgsql-performance@postgresql.org, Gabrielle Roth , Selena Deckelmann Subject: Re: Effects of setting linux block device readahead size References: <70c01d1d0809092353r4ae687a3ycf3d99d43a5680cf@mail.gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Plusnet-Relay: 6ee11b7885745856c5cf31ae9f9cdd38 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200809/128 X-Sequence-Number: 31441 Greg Smith wrote: > Average seek time: 4ms > Seeks/second: 250 > Data read/seek: 1MB (read-ahead number goes here) > Total read bandwidth: 250MB/s > Most spinning disks now are nearer to 100MB/s streaming. You've talked yourself into twice that, random access! James