Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id 721EF9FC23B for ; Wed, 4 Apr 2007 15:09:24 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024) with ESMTP id 98724-01-10 for ; Wed, 4 Apr 2007 15:09:05 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from mail.polimetrix.com (mail.polimetrix.com [209.128.109.230]) by postgresql.org (Postfix) with ESMTP id E4BF59FC120 for ; Wed, 4 Apr 2007 15:03:30 -0300 (ADT) Received: from [10.1.1.201] ([10.1.1.201]) by mail.polimetrix.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.1830); Wed, 4 Apr 2007 11:03:27 -0700 Message-ID: <4613E86B.2080704@polimetrix.com> Date: Wed, 04 Apr 2007 11:03:23 -0700 From: Geoff Tolley User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.10) Gecko/20070226 CentOS/1.0.8-0.2.el4.centos SeaMonkey/1.0.8 MIME-Version: 1.0 To: david@lang.hm CC: Ron , "jason@ohloh.net" , pgsql-performance@postgresql.org Subject: Re: SCSI vs SATA References: <9C0858F5-0A48-4AF9-80FF-E4BA14F0F965@ohloh.net> <4613053F.5070401@polimetrix.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 04 Apr 2007 18:03:27.0314 (UTC) FILETIME=[8B7BAB20:01C776E3] X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200704/83 X-Sequence-Number: 23960 david@lang.hm wrote: > for that matter, with 20ish 320G drives, how large would a parition be > that only used the outer pysical track of each drive? (almost certinly > multiple logical tracks) if you took the time to set this up you could > eliminate seeking entirely (at the cost of not useing your capacity, but > since you are considering a 12x range in capacity, it's obviously not > your primary concern) Good point: if 8x73GB in a RAID10 is an option, the database can't be larger than 292GB, or 1/12 the available space on the 320GB SATA version. > note that the CMU and Google studies both commented on being surprised > at the lack of difference between the reliability of SCSI and SATA drives. I'd read about the Google study's conclusions on the failure rate over time of drives; I hadn't gotten wind before of it comparing SCSI to SATA drives. I do wonder what their access patterns are like, and how that pertains to failure rates. I'd like to think that with smaller seeks (like in the many-big-SATAs-option) the life of the drives would be longer. Oh, one big advantage of SATA over SCSI: simple cabling and no need for termination. Although SAS levels that particular playing field. Cheers, Geoff