From owner-freebsd-performance@FreeBSD.ORG Sun Oct 29 17:59:36 2006 Return-Path: X-Original-To: performance@freebsd.org Delivered-To: freebsd-performance@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6AA9816A415 for ; Sun, 29 Oct 2006 17:59:36 +0000 (UTC) (envelope-from killing@multiplay.co.uk) Received: from multiplay.co.uk (core6.multiplay.co.uk [85.236.96.23]) by mx1.FreeBSD.org (Postfix) with ESMTP id A7A2743D68 for ; Sun, 29 Oct 2006 17:59:32 +0000 (GMT) (envelope-from killing@multiplay.co.uk) Received: from vader ([85.236.96.60]) by multiplay.co.uk (multiplay.co.uk [85.236.96.23]) (MDaemon PRO v9.0.1) with ESMTP id md50003148384.msg for ; Sun, 29 Oct 2006 17:58:55 +0000 Message-ID: <003f01c6fb83$e4b96280$b3db87d4@multiplay.co.uk> From: "Steven Hartland" To: "Petri Helenius" , , "Steve Peterson" References: <6.2.3.4.0.20061027180329.020bed68@localhost><4542D941.2070204@centtech.com><6.2.3.4.0.20061028124559.02105930@localhost><4543AD35.30205@he.iki.fi> <6.2.3.4.0.20061029095927.05833580@localhost> Date: Sun, 29 Oct 2006 17:58:44 -0000 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 X-Spam-Processed: multiplay.co.uk, Sun, 29 Oct 2006 17:58:55 +0000 (not processed: message from valid local sender) X-MDRemoteIP: 85.236.96.60 X-Return-Path: killing@multiplay.co.uk X-MDaemon-Deliver-To: performance@freebsd.org X-MDAV-Processed: multiplay.co.uk, Sun, 29 Oct 2006 17:58:55 +0000 Cc: Subject: Re: gvinum raid5 performance seems slow X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Oct 2006 17:59:36 -0000 Steve Peterson wrote: > I guess the fundamental question is this -- if I have a 4 disk > subsystem that supports an aggregate ~100MB/sec transfer raw to the > underlying disks, is it reasonable to expect a ~5MB/sec transfer rate > for a RAID5 hosted on that subsystem -- a 95% overhead. Absolutely not, when I was investigating RAID5 performance the quickest option I found was linux's software RAID which gave performance of 270MB/s iirc across 5 * 400Gb Disks on a Highpoint 1820a. While doing this I gave givnum a quick test and saw similar results as you so gave up with it as I didnt have time to investigate further. Steve ================================================ This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337 or return the E.mail to postmaster@multiplay.co.uk.