From owner-freebsd-performance@FreeBSD.ORG Mon Oct 3 07:55:58 2005 Return-Path: X-Original-To: freebsd-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 53DFB16A41F for ; Mon, 3 Oct 2005 07:55:58 +0000 (GMT) (envelope-from patpro@patpro.net) Received: from smtp.univ-lyon2.fr (smtp.univ-lyon2.fr [159.84.143.102]) by mx1.FreeBSD.org (Postfix) with ESMTP id DA89443D4C for ; Mon, 3 Oct 2005 07:55:57 +0000 (GMT) (envelope-from patpro@patpro.net) Received: from localhost (localhost [127.0.0.1]) by smtp.univ-lyon2.fr (Postfix) with ESMTP id 7006E170E0AD; Mon, 3 Oct 2005 09:55:56 +0200 (CEST) Received: from smtp.univ-lyon2.fr ([127.0.0.1]) by localhost (smtp.univ-lyon2.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 12936-04; Mon, 3 Oct 2005 09:55:50 +0200 (CEST) Received: from [159.84.142.75] (dhcp-159-84-142-75.univ-lyon2.fr [159.84.142.75]) by smtp.univ-lyon2.fr (Postfix) with ESMTP id C6D79170E081; Mon, 3 Oct 2005 09:55:50 +0200 (CEST) In-Reply-To: <43401C62.2040606@centtech.com> References: <20051002170446.78674.qmail@web30303.mail.mud.yahoo.com> <43401C62.2040606@centtech.com> Mime-Version: 1.0 (Apple Message framework v734) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <618C4F4D-A3F6-4F34-9352-C7C86DC1DD9E@patpro.net> Content-Transfer-Encoding: 7bit From: Patrick Proniewski Date: Mon, 3 Oct 2005 09:55:49 +0200 To: Eric Anderson X-Mailer: Apple Mail (2.734) X-Virus-Scanned: amavisd-new at univ-lyon2.fr Cc: freebsd-performance@freebsd.org, "=?ISO-8859-1?Q? Arne_\"W=F6rner\" ?=" Subject: Re: dd(1) performance when copiing a disk to another 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: Mon, 03 Oct 2005 07:55:58 -0000 Hi Arne and Eric, >>> # atacontrol mode 0 >>> Master = BIOSPIO >>> Slave = BIOSPIO >> Hmm... 0 seems to be the wrong ata... Thats why the output does >> not fit to SATA drives, I think... oups... I'll have to do it again with channels 2 and 3 >>> # dd if=/dev/ad4 of=/dev/null bs=1m count=1000 >>> 1000+0 records in >>> 1000+0 records out >>> 1048576000 bytes transferred in 17.647464 secs (59417943 >>> bytes/sec) >> That seems to be 2 or about 2 times faster than disc->disc >> transfer... But still slower, than I would have expected... >> SATA150 sounds like the drive can do 150MB/sec... As Eric pointed out, you just can"t reach 150 MB/s with one disk, it's a technological maximum for the bus, but real world performance is well bellow this max. In fact, I've though I would reach about 50 to 60 MB/s. >>>> (Maybe you could find a way to copy /dev/zero to /dev/ad6 >>>> without destroying the previous work... :-)) >>> >>> well, not very easy both disk are the same size ;) >> I thought of the first 1000 1MB blocks... :-) damn, I misread this one... :) I'm gonna try this asap. > Instead of dd, why not use gmirror? I had no idea gmirror exists, but I'll continue with dd. It's a one time experiment. > Have you tried a smaller block size? What does 8k, 16k, or 512k do > for you? There really isn't much room for improvement here on a > single device. nop, I'll try one of them, but I can't do many experiments, the box is in my living room, it's a 1U rack, and it's VERY VERY noisy. My girlfriend will kill me if it's running more than an hour a day :)) Pat