From owner-freebsd-mobile Fri Sep 28 7:18:31 2001 Delivered-To: freebsd-mobile@freebsd.org Received: from mail.boulderlabs.com (mail.boulderlabs.com [206.168.112.48]) by hub.freebsd.org (Postfix) with ESMTP id 623F437B40F for ; Fri, 28 Sep 2001 07:18:28 -0700 (PDT) Received: from calypso.boulderlabs.com (cpe-24-221-212-162.co.sprintbbd.net [24.221.212.162]) by mail.boulderlabs.com (8.9.3/8.9.3) with ESMTP id IAA43247; Fri, 28 Sep 2001 08:18:04 -0600 (MDT) (envelope-from bob@cs.colorado.edu) Received: from calypso.boulderlabs.com (localhost [127.0.0.1]) by calypso.boulderlabs.com (980427.SGI.8.8.8/8.8.5) with ESMTP id IAA30085; Fri, 28 Sep 2001 08:18:02 -0600 (MDT) Message-Id: <200109281418.IAA30085@calypso.boulderlabs.com> From: Robert Gray To: "Daniel O'Connor" Cc: Edwin Culp , freebsd-mobile@FreeBSD.ORG, kjerste soderberg Subject: Re: cloning laptop drives In-reply-to: Your message of "Fri, 28 Sep 2001 15:46:43 +0930." Date: Fri, 28 Sep 2001 08:18:01 -0600 Sender: owner-freebsd-mobile@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Yes, like Daniel says, large block sizes (I use 32K or 64K) and separate IDE controllers make a huge difference. You may as well use the "raw" devices to transfer directly into user space. One further tip, /usr/ports/misc/buffer, can double the speed because it forks into two processes connected via shared memory - a reader and a writer, each operating as fast as the disks can respectively read or write. In contrast, dd waits for a read to complete before starting a write. Buffer also prints progress so you know how long it will take. Here is approximately what I use: buffer -s 32k -S 1m /dev/rad1 -s is the block size -S prints out progress "Daniel O'Connor" Fri, 28 Sep 2001 15:46:43 +0930 says: > >On 28-Sep-2001 Edwin Culp wrote: >> AFAIK, the default for dd is one block at a time and that can take for ever >. >> You need to define the block size to something much larger. I have seen >> some >> cool formulas based on disk geometry but I never seem to remember them when >> I need them.:-( You might try something like >> >> dd if=/dev/ad0 of=/dev/ad1 bs=8192 >> >> Hopefully someone will give you a better number. > >I usually pick 64k when doing this.. > >Also, if those drives are on the same chain the performance is going to suck >really hard.. > >If you hit 'ctrl-t' you will get some info on dd's progress, and if you run >'systat -vmstat 1' and look at the bottom section you'll see the transfer >speeds. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-mobile" in the body of the message