From owner-freebsd-hackers@FreeBSD.ORG Sun Feb 12 12:47:10 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4B4D716A420 for ; Sun, 12 Feb 2006 12:47:10 +0000 (GMT) (envelope-from soralx@cydem.org) Received: from pd4mo3so.prod.shaw.ca (shawidc-mo1.cg.shawcable.net [24.71.223.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id E575343D46 for ; Sun, 12 Feb 2006 12:47:08 +0000 (GMT) (envelope-from soralx@cydem.org) Received: from pd4mr7so.prod.shaw.ca (pd4mr7so-qfe3.prod.shaw.ca [10.0.141.84]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0IUK0004KRFLRIB0@l-daemon> for freebsd-hackers@freebsd.org; Sun, 12 Feb 2006 05:45:21 -0700 (MST) Received: from pn2ml2so.prod.shaw.ca ([10.0.121.146]) by pd4mr7so.prod.shaw.ca (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0IUK00DRVRFLLOD0@pd4mr7so.prod.shaw.ca> for freebsd-hackers@freebsd.org; Sun, 12 Feb 2006 05:45:21 -0700 (MST) Received: from soralx.cydem.org ([24.85.63.128]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0IUK00BDORFL6GA0@l-daemon> for freebsd-hackers@freebsd.org; Sun, 12 Feb 2006 05:45:21 -0700 (MST) Date: Sun, 12 Feb 2006 04:45:21 -0800 From: soralx@cydem.org In-reply-to: <20060212122513.GA58153@outcold.yadt.co.uk> To: davidt@yadt.co.uk Message-id: <200602120445.21139.soralx@cydem.org> MIME-version: 1.0 Content-type: text/plain; charset=iso-8859-15 Content-transfer-encoding: 7bit Content-disposition: inline References: <200602112334.k1BNYf83084494@gate.bitblocks.com> <200602120127.03988.soralx@cydem.org> <20060212122513.GA58153@outcold.yadt.co.uk> User-Agent: KMail/1.5.4 Cc: freebsd-hackers@freebsd.org Subject: Re: RAID5 on athlon64 machines X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Feb 2006 12:47:10 -0000 > On Sun, 12 Feb 2006, soralx@cydem.org wrote: > [missing attribution] > > > > You compute max data rates by considering the most optimistic > > > scenario, which is large sequetial writes. For *this* > > > situation write rate will be higher than a single disk's. > > > > How can the RAID5 write rate be higher for the whole array if not > > only it needs to write the data to all if its drives, but also > > compute and write a parity block? > > Easy, you can write simultaneously to more than one drive, assuming > the drive was the bottleneck in the first place. Sorry, my mistake. Confused some RAID levels... Of course, with RAID5, the data block will be split (not mirrored) across several drives (plus a parity block will be added). Perhaps the original poster (bitblocks.com!bakul) may want to resend his question? Since he's experiencing performance problems with gvinum, this could very well be a hackers@ question; some more details may be needed, though. I apologize for all the confusion created here. Timestamp: 0x43EF2B47 [SorAlx] http://cydem.org.ua/ ridin' VN1500-B2