From owner-freebsd-hackers@FreeBSD.ORG Thu Jan 12 21:41:34 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DD9DE16A41F for ; Thu, 12 Jan 2006 21:41:34 +0000 (GMT) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (gate.funkthat.com [69.17.45.168]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7781143D45 for ; Thu, 12 Jan 2006 21:41:34 +0000 (GMT) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (localhost.funkthat.com [127.0.0.1]) by hydrogen.funkthat.com (8.13.3/8.13.3) with ESMTP id k0CLf3Cs006320; Thu, 12 Jan 2006 13:41:03 -0800 (PST) (envelope-from jmg@hydrogen.funkthat.com) Received: (from jmg@localhost) by hydrogen.funkthat.com (8.13.3/8.13.3/Submit) id k0CLf2cA006319; Thu, 12 Jan 2006 13:41:02 -0800 (PST) (envelope-from jmg) Date: Thu, 12 Jan 2006 13:41:01 -0800 From: John-Mark Gurney To: Ivan Voras Message-ID: <20060112214101.GL69162@funkthat.com> Mail-Followup-To: Ivan Voras , freebsd-hackers@freebsd.org References: <20060112153919.GA21009@dan.emsphone.com> <200601121738.k0CHcbQh063237@gate.bitblocks.com> <43C69664.2070505@fer.hr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43C69664.2070505@fer.hr> User-Agent: Mutt/1.4.2.1i X-Operating-System: FreeBSD 5.4-RELEASE-p6 i386 X-PGP-Fingerprint: B7 EC EF F8 AE ED A7 31 96 7A 22 B3 D8 56 36 F4 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html Cc: freebsd-hackers@freebsd.org Subject: Re: increasing dd disk to disk transfer rate X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: John-Mark Gurney List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Jan 2006 21:41:35 -0000 Ivan Voras wrote this message on Thu, Jan 12, 2006 at 18:48 +0100: > Bakul Shah wrote: > >>In the last episode (Jan 12), Christoph Kukulies said: > > >>dd if=/dev/ad2 conv=noerror,sync bs=64k | dd of=/dev/ad3 bs=64k > > > > > >So now on the new disk he has files with random blocks of > >zeroes and *no* error indication of which files are so > >trashed. This is asking for trouble. Silent erros are > >worse. > > > >He ought to do a file level copy, not disk level copy on > >unix. That way he knows *which* files are trashed and can do > > The problem is, FreeBSD panics when it encounters bad sectors in > filesystem metadata. I had the same situation ~a month ago and gave up, > restoring from old backups. It will also probably panic on corrupted or > zeroed metadata, but at least it's on a readable disk... Recovery can be possible with ffsrecov.py: http://people.freebsd.org/~jmg/ffsrecov/ -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."