From owner-freebsd-questions Wed Sep 15 3:13:53 1999 Delivered-To: freebsd-questions@freebsd.org Received: from hera.webcom.com (hera.webcom.com [209.1.28.42]) by hub.freebsd.org (Postfix) with ESMTP id 00E1914C37 for ; Wed, 15 Sep 1999 03:13:47 -0700 (PDT) (envelope-from graeme@echidna.com) Received: from eresh.webcom.com (eresh.webcom.com [209.1.28.49]) by hera.webcom.com (8.9.1/8.9.1) with SMTP id DAA19887; Wed, 15 Sep 1999 03:13:44 -0700 Received: from [204.143.69.49] by inanna.webcom.com (WebCom SMTP 1.2.1) with SMTP id 40383184; Wed Sep 15 03:08 PDT 1999 Message-Id: <37DF9B61.22D7@echidna.com> Date: Wed, 15 Sep 1999 06:13:05 -0700 From: Graeme Tait Organization: Echidna X-Mailer: Mozilla 2.02 (Win16; I) Mime-Version: 1.0 To: Woody Carey , questions@freebsd.org, andriss@andriss.com Cc: info@boatbooks.com Subject: Re: SCSI drive mirroring question References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG I've used dd successfully to replicate a drive to an identical drive, and it may well be much faster than file-by-file methods, depending on what is on the drive to be copied (in particular, how full the drive is). BTW, I believe this also copies any boot record, etc. But this was with the source drive mounted read-only. What would happen if dd was used to copy a live filesystem, and when the system wrote a given file, data was written both before and after the current read point for dd? Woody Carey wrote: > > I was under the impression that 'dd' could be used for bit-by-bit copy. > Can anyone second this? > > - Woody > > > > > What I want is a true bit by bit mirror of the entire first drive... > > > > Can anyone suggest something that would do it? > > > > Andriss -- Graeme Tait - Echidna To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message