From owner-freebsd-stable@FreeBSD.ORG Wed Oct 25 14:06:57 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5B5B816A494; Wed, 25 Oct 2006 14:06:57 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from sccrmhc14.comcast.net (sccrmhc14.comcast.net [63.240.77.84]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1D28543D81; Wed, 25 Oct 2006 14:05:48 +0000 (GMT) (envelope-from jdc@koitsu.dyndns.org) Received: from icarus.home.lan (c-67-174-220-97.hsd1.ca.comcast.net[67.174.220.97]) by comcast.net (sccrmhc14) with ESMTP id <2006102514054701400qpe60e>; Wed, 25 Oct 2006 14:05:48 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id 40F4E1FA037; Wed, 25 Oct 2006 07:05:47 -0700 (PDT) Date: Wed, 25 Oct 2006 07:05:47 -0700 From: Jeremy Chadwick To: Guido van Rooij Message-ID: <20061025140547.GA94660@icarus.home.lan> Mail-Followup-To: Guido van Rooij , "Patrick M. Hausen" , Rink Springer , freebsd-stable@freebsd.org References: <20061025100759.GA50625@gvr.gvr.org> <20061025101801.GE23885@rink.nu> <20061025103905.GB50937@gvr.gvr.org> <20061025104829.GA41873@hugo10.ka.punkt.de> <20061025132455.GA52157@gvr.gvr.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061025132455.GA52157@gvr.gvr.org> X-PGP-Key: http://jdc.parodius.com/pubkey.asc User-Agent: Mutt/1.5.13 (2006-08-11) Cc: Rink Springer , freebsd-stable@freebsd.org Subject: Re: Gmirror performanc (was Re: Gmirror question) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 Oct 2006 14:06:57 -0000 On Wed, Oct 25, 2006 at 03:24:55PM +0200, Guido van Rooij wrote: > Anyway, I created a gm device and a partition. Now the read performance > is not what I'd expect. > I have the partition on two SATA devices on different controlers. > I get around 60MB/s for each disk. I can get that speed from both disks > simultaneously. > Now when I dd from the gm device, I don't get any speed higher than that. > I tried with -b split -s , -b round-robin, -b load. > (dd-ing as done with a bs of 1m; I see the transaction size is 128Kb, > unless the split method is used, in which case the transaction size > gies down. When round-robin is used, the transaction size is 128Kb/s, > but the number of transaction per second goes down.). Do not use dd to benchmark disks. It's not a viable method of benchmarking. Consider installing ports/benchmarks/bonnie++. -- | 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 |