From owner-freebsd-performance@FreeBSD.ORG Mon Oct 3 14:55:43 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 E5E9916A41F for ; Mon, 3 Oct 2005 14:55:43 +0000 (GMT) (envelope-from tuliogs@pgt.mpt.gov.br) Received: from mail.pgt.mpt.gov.br (mail.pgt.mpt.gov.br [200.157.62.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1DE2243D45 for ; Mon, 3 Oct 2005 14:55:42 +0000 (GMT) (envelope-from tuliogs@pgt.mpt.gov.br) Received: from [10.0.0.136] (516e.pgt.mpt.gov.br [10.0.0.136]) by mail.pgt.mpt.gov.br (8.13.1/8.13.1) with ESMTP id j93EteiT066135 for ; Mon, 3 Oct 2005 11:55:40 -0300 (BRST) (envelope-from tuliogs@pgt.mpt.gov.br) Message-ID: <434146CA.8010803@pgt.mpt.gov.br> Date: Mon, 03 Oct 2005 11:57:14 -0300 From: =?ISO-8859-1?Q?Tulio_Guimar=E3es_da_Silva?= User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-performance@freebsd.org References: <20051002170446.78674.qmail@web30303.mail.mud.yahoo.com> <004701c5c77e$a8ab4310$b3db87d4@multiplay.co.uk> In-Reply-To: <004701c5c77e$a8ab4310$b3db87d4@multiplay.co.uk> Content-Type: multipart/mixed; boundary="------------030603030606000800030004" X-Content-Filtered-By: Mailman/MimeDel 2.1.5 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 14:55:44 -0000 This is a multi-part message in MIME format. --------------030603030606000800030004 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Steven Hartland wrote: > ----- Original Message ----- From: "Arne Wörner" > >> 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... > > > LOL, you might want to read up on what SATA150 means. > In short it the max throughput the interface can sustain. It is NOT > what you can get of a single disk which is still fare from that, > SATA disk transfer rates typically 30 -> 50MB/s sustained. > > Steve Indeed. In other words, that represents the max transfer rates between the SATA controller and the disk´s controller (at best, you´ll get close to it when reading from the disk´s onboard cache), but the media will always be much slower. But just to clear out some questions... 1) Maxtor´s full specifications for Diamond Max+ 9 Series refers to maximum *sustained* transfer rates of 37MB/s and 67MB/s for "ID" and "OD", respectively (though I couldn´d find exactly what it means, I deduced that represents the rates for center- and border-parts of the disk - please correct me if I´m wrong), then your tests show you´re getting the best out of it ;) ; 2) Mr. Hartland mentioned the numbers to be good for a single drive, therefore it´s a bit better for a disk-to-disk, where the limit should be the slower disk´s performance. I couldn´t look for the specs of the Toshiba since I didn´t have the exact model, but I would expect it to be equal or faster than the Maxtor, since it does not appear to be a bottleneck. One last thought, though, for the specialists: iostat showed maximum of 128KB/transfer, even though dd should be using 1MB blocks... is that an expected behaviour? Shouldn´t iostat show 1024Kb/t, then? Thanks for your attention, Tulio G. da Silva --------------030603030606000800030004--