From owner-freebsd-questions Sun Sep 30 13:59:43 2001 Delivered-To: freebsd-questions@freebsd.org Received: from guru.mired.org (okc-94-248-46.mmcable.com [24.94.248.46]) by hub.freebsd.org (Postfix) with SMTP id 9E43537B40B for ; Sun, 30 Sep 2001 13:59:37 -0700 (PDT) Received: (qmail 20685 invoked by uid 100); 30 Sep 2001 20:59:36 -0000 From: Mike Meyer MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15287.34744.739567.546962@guru.mired.org> Date: Sun, 30 Sep 2001 15:59:36 -0500 To: "Mario Doria" Cc: questions@freebsd.org Subject: Re: Copy a disk using dd In-Reply-To: <113500895@toto.iv> X-Mailer: VM 6.90 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid X-face: "5Mnwy%?j>IIV\)A=):rjWL~NB2aH[}Yq8Z=u~vJ`"(,&SiLvbbz2W`;h9L,Yg`+vb1>RG% *h+%X^n0EZd>TM8_IB;a8F?(Fb"lw'IgCoyM.[Lg#r\ Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Mario Doria types: > Hi, > > On some machine with 2 identical disks, I want to copy everything on the > first drive to the second drive (mirror copy). The disks are da0 and da1. > I'm thinking of using: > > dd if=/dev/da0 of=/dev/da1 bs=8192 > > Is this OK? Yes, provided that none of the file systems on da0 are active, and none of the ones on da1 are mounted. Doing it single user without mounting anything or enabling swap is recommended. I would recommend a *much* larger block size, though. At least a half-cylinder, though if you can fit multiple cylinders memory without swap, as many as you can fit is fine. http://www.mired.org/home/mwm/ Q: How do you make the gods laugh? A: Tell them your plans. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message