From owner-freebsd-questions@FreeBSD.ORG Sun Nov 30 19:27:12 2003 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id ED96416A4CE for ; Sun, 30 Nov 2003 19:27:12 -0800 (PST) Received: from m01.ca.astound.net (m01.ca.astound.net [64.85.239.11]) by mx1.FreeBSD.org (Postfix) with ESMTP id 22CF443FAF for ; Sun, 30 Nov 2003 19:27:12 -0800 (PST) (envelope-from rchopra@cal.berkeley.edu) Received: from cal.berkeley.edu (astound-66-234-212-148.ca.astound.net [66.234.212.148]) by m01.ca.astound.net (8.12.10/8.12.10) with ESMTP id hB13Pgc3007796 for ; Sun, 30 Nov 2003 19:25:42 -0800 Message-ID: <3FCAB50A.8090705@cal.berkeley.edu> Date: Sun, 30 Nov 2003 19:27:06 -0800 From: Rishi Chopra User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5b) Gecko/20030901 Thunderbird/0.2 X-Accept-Language: en-us, en MIME-Version: 1.0 To: questions@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new Subject: Raid Array Stripe Size Investigation X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Dec 2003 03:27:13 -0000 After some initial trouble getting my FreeBSD box up and running, I'm happy to report that I've been able to conduct a few empirical tests on IDE hardware RAID array stripe size and performance. I decided to do these benchmarks when I noticed a lack of this information on the web and as part of the mailing list. Information on the setup of the tests and results can be found here: http://www.ocf.berkeley.edu/~rchopra/RaidResults.html If anyone would care to add some insight into why Bonnie and IOZone are/aren't good benchmarks for such a test, feel free to share. Also, I didn't bother to write any conclusions to the tests; I merely generated the data. As with everything RAID, there's no 'best' configuration, and it doesn't seem like there was a clear winner as a result. I also doubt whether you could draw any conclusions about the OS and hardware driver implementation. As far as single-user systems go, I don't think you'd see any difference performance-wise regardless of stripe size. If someone can suggest a methodology for multi-user testing, I'd consider giving it a go. NOTE: I do still have a question about large disks. My 4x200 RAID5 array (~550GB) won't load if I tell sysinstall to use the entire disk as one slice, with partitions amongst that slice. Given the large size of the array, I ignored warnings about '# of cylinders' but I'm still curious why I can't use the whole disk as one bootable slice. Any suggestions?