From owner-freebsd-stable@FreeBSD.ORG Thu Nov 3 20:06:28 2005 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 55AC816A41F for ; Thu, 3 Nov 2005 20:06:28 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id DEB6243D45 for ; Thu, 3 Nov 2005 20:06:27 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.13.1/8.13.3) id jA3K6Ror069788; Thu, 3 Nov 2005 14:06:27 -0600 (CST) (envelope-from dan) Date: Thu, 3 Nov 2005 14:06:27 -0600 From: Dan Nelson To: Francisco Reyes Message-ID: <20051103200627.GD67512@dan.emsphone.com> References: <0E972CEE334BFE4291CD07E056C76ED807738005@bragi.housing.ufl.edu> <20051103133248.Y60367@zoraida.natserv.net> <436A5B7D.6090408@mac.com> <20051103143332.B60864@zoraida.natserv.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051103143332.B60864@zoraida.natserv.net> X-OS: FreeBSD 5.4-STABLE X-message-flag: Outlook Error User-Agent: Mutt/1.5.11 Cc: stable@freebsd.org Subject: Re: Disk 100% busy X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Nov 2005 20:06:28 -0000 In the last episode (Nov 03), Francisco Reyes said: > On Thu, 3 Nov 2005, Chuck Swiger wrote: > How about for database? In particular postgresql. > How bad would RAID 5 be for it? > > I still have some, limited, hopes I can convince the owner of the > company to go with RAID 10 with 10K rpm drives.. the most likelyhood > we will go with RAID 5, 7200rpm drives for a database project ahead. > Alternatively I will see how RAID 5 with 10K rpm SCSI drives compares > price wise, but I am sure it will be substantially more. :-( The biggest reason for going RAID-5 is that you only get 50% useable capacity out of RAID 10, and at least 75% out of a RAID 5 (with a 3+1 layout. With an 8+1 layout you get 88%). If you don't need fast writes, or your controller has sufficient cache to mask the write penalty, RAID 5 sure holds a lot more data on the same disks. Always keep your logs on a separate mirrored set of disks, of course. -- Dan Nelson dnelson@allantgroup.com