From owner-freebsd-current@FreeBSD.ORG Thu Oct 18 09:15:31 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AC2D016A418 for ; Thu, 18 Oct 2007 09:15:31 +0000 (UTC) (envelope-from jdc@parodius.com) Received: from mx01.sc1.parodius.com (mx01.sc1.parodius.com [72.20.106.3]) by mx1.freebsd.org (Postfix) with ESMTP id 96BF213C45D for ; Thu, 18 Oct 2007 09:15:31 +0000 (UTC) (envelope-from jdc@parodius.com) Received: by mx01.sc1.parodius.com (Postfix, from userid 1000) id 708A71CC05C; Thu, 18 Oct 2007 02:15:31 -0700 (PDT) Date: Thu, 18 Oct 2007 02:15:31 -0700 From: Jeremy Chadwick To: Stefan Lambrev Message-ID: <20071018091531.GA8737@eos.sc1.parodius.com> Mail-Followup-To: Stefan Lambrev , freebsd-current@freebsd.org References: <47161A42.2050306@moneybookers.com> <471636E4.90807@thekeelecentre.com> <47163ACC.1080807@moneybookers.com> <47163B9B.4010901@thekeelecentre.com> <471715AD.3080102@moneybookers.com> <47171750.8050906@thekeelecentre.com> <20071018085812.GA8481@eos.sc1.parodius.com> <471722BE.20107@moneybookers.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <471722BE.20107@moneybookers.com> User-Agent: Mutt/1.5.16 (2007-06-09) Cc: freebsd-current@freebsd.org Subject: Re: Very slow HP 8 Internal Port SAS HBA with RAID 0, 1 on Hot Plug SAS/SATA Models (LSI SAS1068 - mpt) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Oct 2007 09:15:31 -0000 On Thu, Oct 18, 2007 at 12:09:18PM +0300, Stefan Lambrev wrote: > May be I have wrong impression that mirror should increase read speed > almost twice compared to > single disk, but I forget that bonnie++ was run as single thread. > May be if I start it with concurrency=2 then I'll see the real performance > of the mirror ? > Or should I move to the thread to performance@ :) The easiest way for me to describe it would be to refer you to the Wikipedia article. See the section "Other benefits of mirroring": http://en.wikipedia.org/wiki/Disk_mirror Generally speaking, RAID 1 sequential read across 2 disks should be slightly higher than the same disk in a JBOD configuration -- keyword is "slightly". RAID 0 (striping) is what gives you the immense improvement, but I'm sure you know how risky RAID 0 is... -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |