From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Colls Subject: Re: Raid Problem - Unknown File System Type Date: Wed, 09 Nov 2011 14:57:18 -0500 Message-ID: <4EBADB1E.1070700@rogers.com> References: <4EBAA68B.6090906@rogers.com> <20111109163933.GA26630@cthulhu.home.robinhill.me.uk> <4EBAB47C.5070002@rogers.com> <4EBACC88.8070403@turmel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4EBACC88.8070403@turmel.org> Sender: linux-raid-owner@vger.kernel.org To: Phil Turmel Cc: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids On 11/09/2011 01:55 PM, Phil Turmel wrote: > Hi William, > > On 11/09/2011 12:12 PM, William Colls wrote: > [...] > >> I thought, at the time, that I needed to do the create so that the /dev/md0 device would be created properly (new machine had no raid before). > > That's the "--auto" option, which has sane defaults. > > [...] > >> No output from the original setup. > >> From what you've described so far, a likely possibility is that the original raid 1 was using metadata version 1.1 or 1.2, which put the superblock near the beginning of the disks. The default "--create" metadata in that old version of mdadm is 0.9, as you can see in your reports. > > If so, you've likely only lost a tiny bit of data at the end of the volumes where the 0.90 superblock has been written. (I'm also going to assume that the two disks were in-sync in old box before you moved them, so the re-sync wouldn't do any harm.) > > A dump of the first 8K of your drives might be helpful here. > > dd if=/dev/sdb count=16 2>/dev/null |hexdump -C > > dd if=/dev/sdc count=16 2>/dev/null |hexdump -C > > Regards, > > Phil > Did the dumps to text files. diff shows no difference between the files. Should I be looking for anything particular? There are sections which seem to have data, and several blocks that are all zeros, but I don't see any particular patterns, and only a very few obvious text strings. Thanks for your interest and help. -- I know you believe that you understand what you think I said, but I am not sure that you realize that what you heard was not what I ment.