From owner-freebsd-fs@FreeBSD.ORG Wed Jul 13 15:06:49 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id AC7DD1065674 for ; Wed, 13 Jul 2011 15:06:49 +0000 (UTC) (envelope-from freebsdlists@bsdunix.ch) Received: from conversation.bsdunix.ch (ns1.bsdunix.ch [82.220.1.90]) by mx1.freebsd.org (Postfix) with ESMTP id 678B78FC0C for ; Wed, 13 Jul 2011 15:06:49 +0000 (UTC) Received: from conversation.bsdunix.ch (localhost [127.0.0.1]) by conversation.bsdunix.ch (Postfix) with ESMTP id 249254AA5; Wed, 13 Jul 2011 14:49:47 +0000 (UTC) X-Virus-Scanned: by amavisd-new at mail.bsdunix.ch Received: from conversation.bsdunix.ch ([127.0.0.1]) by conversation.bsdunix.ch (conversation.bsdunix.ch [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Ti9Gnhs5QqPC; Wed, 13 Jul 2011 14:49:46 +0000 (UTC) Received: from ernie.mlan.solnet.ch (ernie.mlan.solnet.ch [212.101.1.20]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by conversation.bsdunix.ch (Postfix) with ESMTPSA id 9452B4A9E; Wed, 13 Jul 2011 14:49:46 +0000 (UTC) Mime-Version: 1.0 (Apple Message framework v1244.3) Content-Type: text/plain; charset=iso-8859-1 From: Thomas Vogt X-Priority: 3 In-Reply-To: <94D74687DE95420486730136248EEB77@multiplay.co.uk> Date: Wed, 13 Jul 2011 16:49:46 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <39788F1B-DCF5-488C-8033-5628B97D4592@bsdunix.ch> References: <69E82BC1AF1E4F50B37119C4E614B190@multiplay.co.uk> <94D74687DE95420486730136248EEB77@multiplay.co.uk> To: Steven Hartland X-Mailer: Apple Mail (2.1244.3) Cc: freebsd-fs@freebsd.org Subject: Re: Forcing a full file read in ZFS even when checksum error encountered X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Jul 2011 15:06:49 -0000 Hi Steven On Jul 13, 2011, at 12:01 PM, Steven Hartland wrote: > ----- Original Message ----- From: "Artem Belevich" >> Maybe. See here: >> http://blogs.oracle.com/relling/entry/holy_smokes_a_holey_file >> Using that method you still would not get the bad block, but you may >> be able to recover data beyond it. >> If you really want to get access to the data that ZFS considers to be >> corrupted, you need to get close and personal with zdb. >> This blog post may be a good starting point: = http://cuddletech.com/blog/?p=3D407 >=20 > Perfect, thanks Artem. >=20 > For the record using the following zdb commands I've managed to get = the > file data off the pool. >=20 > 1. zdb -dddd / (find the objectid by searching for the > filename) > 2. zdb -ddddd / (find the indirect blocks, = the > third block of hex) > 3. zdb -R : 2>/tmp/filedata >=20 > e.g. > zdb -dddd tank/usr > zdb -ddddd tank/usr 1243 > zdb -R tank:0:22df120000:18000:r 2>corrupt.jpg Which ZFS version do you have? zdb core dumps on all my ZFS 28 with = 8-Stable if i use multiple -dd options.=20 Regards, Thomas=20