From owner-freebsd-performance@FreeBSD.ORG Wed Oct 5 17:30:28 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 DED2216A41F for ; Wed, 5 Oct 2005 17:30:28 +0000 (GMT) (envelope-from patpro@patpro.net) Received: from smtp4-g19.free.fr (smtp4-g19.free.fr [212.27.42.30]) by mx1.FreeBSD.org (Postfix) with ESMTP id 823C143D45 for ; Wed, 5 Oct 2005 17:30:28 +0000 (GMT) (envelope-from patpro@patpro.net) Received: from [10.0.2.2] (boleskine.patpro.net [82.235.12.223]) by smtp4-g19.free.fr (Postfix) with ESMTP id 56EA72CB1F for ; Wed, 5 Oct 2005 19:30:27 +0200 (CEST) Mime-Version: 1.0 (Apple Message framework v734) In-Reply-To: References: Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <3509E78F-E90F-4056-AD4C-FDDDC41A4A46@patpro.net> Content-Transfer-Encoding: 7bit From: Patrick Proniewski Date: Wed, 5 Oct 2005 19:30:24 +0200 To: freebsd-performance@freebsd.org X-Mailer: Apple Mail (2.734) 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: Wed, 05 Oct 2005 17:30:29 -0000 Hi, thank you all for these interesting explanations. I've made some more tests with my disks : As you'll see, for block size greater than 64k, the HDD ad6 (hitachi) is the bottleneck. bs of 1m and 512k yield to best transfert rates between ad4 and ad6 and using a pipe between to dd will lower the performance. best regards, and thank you again, Pat, #### /dev/zero to ad6 # dd if=/dev/zero of=/dev/ad6 bs=1m count=1000 1000+0 records in 1000+0 records out 1048576000 bytes transferred in 31.047655 secs (33773114 bytes/sec) # dd if=/dev/zero of=/dev/ad6 bs=8k count=128000 128000+0 records in 128000+0 records out 1048576000 bytes transferred in 31.580223 secs (33203565 bytes/sec) #### ad4 (SATA150) to ad6 (SATA150) # dd if=/dev/ad4 of=/dev/ad6 bs=8k count=128000 128000+0 records in 128000+0 records out 1048576000 bytes transferred in 50.916216 secs (20594146 bytes/sec) # dd if=/dev/ad4 of=/dev/ad6 bs=64k count=16000 16000+0 records in 16000+0 records out 1048576000 bytes transferred in 30.925397 secs (33906630 bytes/sec) # dd if=/dev/ad4 of=/dev/ad6 bs=128k count=8000 8000+0 records in 8000+0 records out 1048576000 bytes transferred in 31.462153 secs (33328170 bytes/sec) # dd if=/dev/ad4 of=/dev/ad6 bs=256k count=4000 4000+0 records in 4000+0 records out 1048576000 bytes transferred in 30.819234 secs (34023428 bytes/sec) # dd if=/dev/ad4 of=/dev/ad6 bs=512k count=2000 2000+0 records in 2000+0 records out 1048576000 bytes transferred in 30.589651 secs (34278783 bytes/sec) # dd if=/dev/ad4 of=/dev/ad6 bs=1m count=1000 1000+0 records in 1000+0 records out 1048576000 bytes transferred in 30.660553 secs (34199514 bytes/sec) # dd if=/dev/ad4 bs=1m count=1000 | dd of=/dev/ad6 bs=1m 1000+0 records in 1000+0 records out 1048576000 bytes transferred in 33.998716 secs (30841635 bytes/sec) 0+16000 records in 0+16000 records out 1048576000 bytes transferred in 34.001099 secs (30839474 bytes/sec)