From owner-freebsd-questions@FreeBSD.ORG Tue Feb 14 14:54:59 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ACCD2106566C for ; Tue, 14 Feb 2012 14:54:59 +0000 (UTC) (envelope-from freebsd-questions-local@be-well.ilk.org) Received: from asbnvacz-mailrelay01.megapath.net (asbnvacz-mailrelay01.megapath.net [207.145.128.243]) by mx1.freebsd.org (Postfix) with ESMTP id 63EFE8FC1C for ; Tue, 14 Feb 2012 14:54:59 +0000 (UTC) Received: from mail1.sea5.speakeasy.net (mail1.sea5.speakeasy.net [69.17.117.39]) by asbnvacz-mailrelay01.megapath.net (Postfix) with ESMTP id 7D49DA7285D for ; Tue, 14 Feb 2012 09:54:55 -0500 (EST) Received: (qmail 21931 invoked from network); 14 Feb 2012 14:54:51 -0000 Received: by simscan 1.4.0 ppid: 16766, pid: 17681, t: 0.1830s scanners: clamav: m: Received: from unknown (HELO be-well.ilk.org) ([66.92.78.145]) (envelope-sender ) by mail1.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 14 Feb 2012 14:54:50 -0000 Received: by be-well.ilk.org (Postfix, from userid 1147) id 2FC9B33C1D; Tue, 14 Feb 2012 09:54:50 -0500 (EST) From: Lowell Gilbert To: "Pegasus Mc Cleaft" References: <005201cceacb$884ead60$98ec0820$@com> Date: Tue, 14 Feb 2012 09:54:50 -0500 In-Reply-To: <005201cceacb$884ead60$98ec0820$@com> (Pegasus Mc Cleaft's message of "Tue, 14 Feb 2012 03:48:35 -0000") Message-ID: <44lio5ihxh.fsf@be-well.ilk.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: '_' , 'freebsd-questions' Subject: Re: corrupted tar.gz archive - I lost my backups :)/:( X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-questions@freebsd.org List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Feb 2012 14:54:59 -0000 "Pegasus Mc Cleaft" writes: >> It recreates something, but the most important files, which reside in >> subfolders of the given tar.gz archives are gone, i.e. the subfolders >> are empty. >> The gunzip strategy you mentioned yields the same as a regular tar -xvf >> file.tar.gz. >> >> Pegasus, I have yet to try the pax(1) approach. I will let you know >> about how that went. > > Hummmmm.. I'm not sure if pax will be able to help in this case. From the > looks of it, somehow the compressed data got corrupted - I don't think pax > will be able to deal with this any better than tar did. Probably correct; the right data isn't there, no tool is going to be able to recover it. Data compression makes this more fragile (i.e., lose the rest of the archive as opposed to only the files in which the data corruption occurs. > I wonder if there was a change in gzip (like maybe libarchive) between the > two versions of BSD that might be causing the problem. If I were attacking > the problem, I might try booting up off a 7.x bootcd and see if I can gzip > --test the archive from the usb stick. It's easy enough to try, but it seems awfully unlikely to help; lots of us have .tar.gz files going back a couple of decades, and if there were ever new implementations that couldn't understand the old ones, some old hand would have noticed by now. Media errors happen, and preparing for them involves noticing them before you try to use the data, as well as recovering if they go bad. The user seems to have knowingly only had one copy of the valuable data, which makes the word "backup" a bit of an unusual usage of the term... --Lowell