From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k4VCk4Iq025736 for ; Wed, 31 May 2006 08:46:04 -0400 Received: from wirenth.dragonhold.org (wirenth.dragonhold.org [217.147.94.178]) by mx3.redhat.com (8.13.1/8.13.1) with ESMTP id k4VCjquZ020402 for ; Wed, 31 May 2006 08:45:57 -0400 Received: from gwood by wirenth.dragonhold.org with local (Exim 4.50) id 1FlQ54-0001QT-Ti for linux-lvm@redhat.com; Wed, 31 May 2006 13:45:46 +0100 Date: Wed, 31 May 2006 13:45:46 +0100 From: Graham Wood Subject: Re: [linux-lvm] rescue data after hd crash Message-ID: <20060531124546.GF13142@dragonhold.org> References: Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: LVM general discussion and development On Wed, May 31, 2006 at 02:34:04PM +0200, chris wrote: > I have create a volume group with 4 250GByte harddisks with an ext3 file > system on the 1TB result. Stripe or concat? > now the third harddisk failed and the volume group is "dead" - obviously. The way you created the volume had no redundancy - therefore 25% of your data is gone, as well as the volume's "completeness". If you did a concat, then you (with playing) may be able to get some data back from the first 500GB of the volume - but I wouldn't want to rely on anything that came back from it. I'd suggest getting hold of 2 identical blank disks, and doing a binary (dd) copy of disks 1 and 2 to them - and then work on them. You might be able to use vgcfg{backup,restore} to tell the system that this volume is actually only on 2 disks.... However, anything that references data > 500GB into the volume is almost definitely lost - because although you've got 750G-1TB, it's almost all going to be linked back into the section that you've lost. If you did a stripe, then you can forget getting any data back off it. You've lost every 4th block of whatever size you striped on. E.g. with a 64k stripe size, you'll have lost from 128k-192k, 384k-448k, etc. - and there's almost definitely going to be nothing salvagable from that. Graham