Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 29FB264FE1D for ; Tue, 9 Dec 2008 16:12:43 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 59302-07 for ; Tue, 9 Dec 2008 16:12:39 -0400 (AST) X-Greylist: delayed 00:05:09.420023 by SQLgrey-1.7.6 Received: from mail-bw0-f20.google.com (mail-bw0-f20.google.com [209.85.218.20]) by mail.postgresql.org (Postfix) with ESMTP id E4EDE64FDA5 for ; Tue, 9 Dec 2008 16:12:38 -0400 (AST) Received: by bwz13 with SMTP id 13so272708bwz.19 for ; Tue, 09 Dec 2008 12:12:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=Kcz/kmKwMqYOz4Dy7I+VvGeYuxPTdzdnCVTfc02GGZQ=; b=Nv5A7rDUBD1APWYlYuTGPA58EnPE8abOc+J8ylzrJoMDl+kPpCFGCRMsP40qVcqyBt lmRnVxzI6g1fGfsVzP7LH6lG4GEAc4DnudltOQQcWklazPP5SXpJb734wfwhB3GKt1xS Ivn+klrtc+kVHm7eZYT9qP6rOs3uC27fI/1AY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=PDp/X5QUnhAnaMFUnhRlGq2uwK101bW2mkY285PJKJ5xcOZOe6pONyv8y8nhy92oxQ cKrstwEOqtheIlk6nMNYfyCZCOO9mk734YQvpBSGnBAuBoZD0rPKgbJGv/OGQKkD93eQ 6HDjsAF4Cu3h1gIPa3LvRM9eF3wJ7Q4vjaAkI= Received: by 10.103.11.7 with SMTP id o7mr212706mui.103.1228853224638; Tue, 09 Dec 2008 12:07:04 -0800 (PST) Received: by 10.103.131.10 with HTTP; Tue, 9 Dec 2008 12:07:04 -0800 (PST) Message-ID: Date: Tue, 9 Dec 2008 15:07:04 -0500 From: "Merlin Moncure" To: jd@commandprompt.com Subject: Re: Need help with 8.4 Performance Testing Cc: "Scott Marlowe" , "Scott Carey" , "Jean-David Beyer" , "pgsql-performance@postgresql.org" In-Reply-To: <1228846285.13962.42.camel@jd-laptop.pragmaticzealot.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1228846285.13962.42.camel@jd-laptop.pragmaticzealot.org> 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: 200812/89 X-Sequence-Number: 32125 On Tue, Dec 9, 2008 at 1:11 PM, Joshua D. Drake wrote: > Hard drives work, their cheap and fast. I can get 25 spindles, 15k in a > 3U with controller and battery backed cache for <$10k. While I agree with your general sentiments about early adoption, etc (the intel ssd products are the first flash drives that appear to have real promise in the enterprise), the numbers tell a different story. A *single* X25-E will give similar sustained write IOPS as your tray for far less price and a much better worst case read latency. All this without the 25 sets of whizzing ball bearings, painful spin-up times, fanning, RAID controller firmware, and various other sundry technologies to make the whole thing work. The main issue that I see with flash SSD is if the promised wear lifetimes are believable in high load environments and the mechanism of failure (slowly degrade into read only) is accurate. So, at least in relative terms, 15k sas drives are not 'fast'. They are terribly, awfully, painfully slow. They are also not cheap in terms of $/IOPS. The end is near. merlin