From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Clements Subject: Re: Zero Superblock... any ways to recover? Date: Mon, 01 Mar 2004 14:31:07 -0500 Sender: linux-raid-owner@vger.kernel.org Message-ID: <40438F7B.2CAE0B21@SteelEye.com> References: <20040301181240.GC4340@percy.comedia.it> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Luca Berra wrote: > > On Mon, Mar 01, 2004 at 03:23:43PM +0100, Timo.Bolse@SerNet.DE wrote: > >pentium-test:/proc/ide # mdadm -E /dev/hdc > >mdadm: No super block found on /dev/hdc (Expected magic a92b4efc, got 00000000) > > > >There must be a way to find the superblock on the new device... is there anyone > >who has a solution for this problem? > > > >I thougt about searching for a92b4efc on the device... If you know how the array was configured, you could just re-create it, which will create a new superblock in the correct location. But if you aren't sure, and you want to search for the superblock, you can do: dd if=/dev/hdc bs=512 | od -A d -h | grep "4efc a92b" That will give you the offset of the superblock. > if you know the size of the old device you can find it starting at > (sector aligned) DEVICE_SIZE - 64k Actually, the superblock is going to be at: sb_offset = size - (size % 64k) - 64k So the superblock is actually somewhere between 64k and 128k from the end of the (old) device. -- Paul