From owner-freebsd-geom@FreeBSD.ORG Mon Nov 11 15:50:46 2013 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id C3120886 for ; Mon, 11 Nov 2013 15:50:46 +0000 (UTC) (envelope-from erichsfreebsdlist@alogt.com) Received: from alogt.com (alogt.com [69.36.191.58]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 9FEB7217C for ; Mon, 11 Nov 2013 15:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=alogt.com; s=default; h=Content-Transfer-Encoding:Content-Type:Mime-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date; bh=Q+LAUrMzSUTT1QPSmwcQhglyzMF+MGNmGPYGZmVq+uA=; b=o2gnr9bDjQfitTxTB+/8kEYUxCeRA3vidb1EYkYZbxyDR4qDaDlldYZ5EknAC3GWqnucSaGwowhMWo5i3FPkFpHwx5UllYrnvgGMu9deMrqzUPYWbTX5FoZuiul3n+gHRsp5lwhJqKfsJpdgC8yaKw+zuwijTt/7CYvcMxKq52s=; Received: from [182.5.85.198] (port=25267 helo=X220.ovitrap.com) by sl-508-2.slc.westdc.net with esmtpsa (SSLv3:DHE-RSA-AES128-SHA:128) (Exim 4.80.1) (envelope-from ) id 1VftlE-0039Sy-Sb; Mon, 11 Nov 2013 08:50:46 -0700 Date: Mon, 11 Nov 2013 23:50:32 +0800 From: Erich Dollansky To: symbolics@gmx.com Subject: Re: documentation of GEOM data structures needed Message-ID: <20131111235032.6a6f26f7@X220.ovitrap.com> In-Reply-To: <20131111151141.GA1381@lemon> References: <20131111162400.0bc7dfef@X220.ovitrap.com> <20131111091836.GA83261@lemon> <20131111183216.5ec80e9e@X220.ovitrap.com> <20131111151141.GA1381@lemon> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.19; amd64-portbld-freebsd10.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - sl-508-2.slc.westdc.net X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - alogt.com X-Get-Message-Sender-Via: sl-508-2.slc.westdc.net: authenticated_id: erichsfreebsdlist@alogt.com X-Source: X-Source-Args: X-Source-Dir: Cc: freebsd-geom@freebsd.org X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Nov 2013 15:50:46 -0000 Hi, On Mon, 11 Nov 2013 15:11:41 +0000 symbolics@gmx.com wrote: > On Mon, Nov 11, 2013 at 06:32:16PM +0800, Erich Dollansky wrote: > > > > On Mon, 11 Nov 2013 09:18:36 +0000 > > symbolics@gmx.com wrote: > > > > > On Mon, Nov 11, 2013 at 04:24:00PM +0800, Erich Dollansky wrote: > > > > > > > > I would need a documentation of the GEOM data structure. A disk > > > > got damages in a strange way during the process of backing up > > > > data. It was partitioned with gpart as all my disks using the > > > > MBR schema. When creating the backup, the system crashed. The > > > > disk was not usable anymore. I found out that the MBR was > > > > overwritten before the backup was started while the beginning > > > > of the first partition seems to be ok. > > > > > > > > I hope to be able to recover the data saving me one week of > > > > work. > > > > > > As I understand things, you believe that your filesystems are > > > okay and you just want to recreate the MBR so you can try to fsck > > > and mount > > > > this is the basic idea. > > > > > them? How did you set the disc MBR up in the first place? If you > > > used the automatic scheme in the installer and you know the size > > > of the > > > > I used the manual way creating 6 partitions. > > Do you know the sizes and order of how they were set up? They're all > UFS2 or a mixture of other things too? they are all UFS plus one swap. I have two other which should have the same partitioning with the exception that the size of the disk differ by a few sectors. This should only affect the end of the size of the last partition. > > > > disc, you could reconstruct things that way. What does `gpart > > > show' look like at the moment? > > > > It does not come that far > > > > gpart list da0 > > gpart: No such geom: da0. > > > > is all I get. > > > > My luck is that I have three disks which are the type but > > manufactured with some months between. But their sizes differ a > > bit. I think that I should be able to recover much by just > > comparing the entries. > > > > You can try looking at diskinfo -v da0 to see the numbers. > 512 # sectorsize 500107860480 # mediasize in bytes (466G) 976773165 # mediasize in sectors 0 # stripesize 0 # stripeoffset 60801 # Cylinders according to firmware. 255 # Heads according to firmware. 63 # Sectors according to firmware. 0000000000006121 # Disk ident. One other disk shows the same data while the third one shows this: 512 # sectorsize 500107862016 # mediasize in bytes (466G) 976773168 # mediasize in sectors 4096 # stripesize 0 # stripeoffset 15504336 # Cylinders according to firmware. 1 # Heads according to firmware. 63 # Sectors according to firmware. TF0504YS02ZPBP # Disk ident. > I had a little play around making a test disc and mdconfig. If I get > some more time this evening I'll see if I can write a tool to scan the > disc and recover the partition data, it'd be a good exercise. > > There are a few programmes in ports/sysutils you should try in the > meantime. I didn't find them useful in my tests but that might not be > indicative of anything. > This I will do tomorrow. Erich