From owner-freebsd-performance@FreeBSD.ORG Thu Apr 28 16:04:32 2005 Return-Path: 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 9B28C16A4CE for ; Thu, 28 Apr 2005 16:04:32 +0000 (GMT) Received: from multiplay.co.uk (www1.multiplay.co.uk [212.42.16.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0935C43D3F for ; Thu, 28 Apr 2005 16:04:32 +0000 (GMT) (envelope-from killing@multiplay.co.uk) Received: from stevenp4 ([193.123.241.40]) by multiplay.co.uk (multiplay.co.uk [212.42.16.7]) (MDaemon.PRO.v8.0.1.R) with ESMTP id md50001366900.msg for ; Thu, 28 Apr 2005 16:59:58 +0100 Message-ID: <070201c54c0b$cd889a00$7f06000a@int.mediasurface.com> From: "Steven Hartland" To: =?iso-8859-1?Q?Arne_W=F6rner?= , "Eric Anderson" References: <20050428155908.41481.qmail@web41201.mail.yahoo.com> Date: Thu, 28 Apr 2005 17:03:22 +0100 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2527 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 X-Spam-Processed: multiplay.co.uk, Thu, 28 Apr 2005 16:59:58 +0100 (not processed: message from valid local sender) X-MDRemoteIP: 193.123.241.40 X-Return-Path: killing@multiplay.co.uk X-MDaemon-Deliver-To: freebsd-performance@freebsd.org X-MDAV-Processed: multiplay.co.uk, Thu, 28 Apr 2005 16:59:58 +0100 cc: freebsd-performance@freebsd.org Subject: Re: Very low disk performance Highpoint 1820a X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Apr 2005 16:04:32 -0000 Only on write this is a read test. ----- Original Message ----- From: "Arne Wörner" > Furthermore RAID-5 needs to read the parity block, before it can > update that block, so that there are 2 disc transactions more, > which could explain the better performance of a single disk, too? > > Or does the striping effect (inherent to RAID-5) compensate those > 2 extra transactions (at least in case of sequential writes)? ================================================ 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 (023) 8024 3137 or return the E.mail to postmaster@multiplay.co.uk.