Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266469AbUA2WkT (ORCPT ); Thu, 29 Jan 2004 17:40:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266471AbUA2WkT (ORCPT ); Thu, 29 Jan 2004 17:40:19 -0500 Received: from hermine.idb.hist.no ([158.38.50.15]:53768 "HELO hermine.idb.hist.no") by vger.kernel.org with SMTP id S266469AbUA2WkL (ORCPT ); Thu, 29 Jan 2004 17:40:11 -0500 Date: Thu, 29 Jan 2004 23:52:40 +0100 To: venom@sns.it Cc: Christoph Hellwig , Dave Kleikamp , Florian Huber , JFS Discussion , linux-kernel Subject: Re: [Jfs-discussion] md raid + jfs + jfs_fsck Message-ID: <20040129225240.GA3118@hh.idb.hist.no> References: <20040127205324.A19913@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.5.1+cvs20040105i From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1692 Lines: 36 On Wed, Jan 28, 2004 at 10:24:14AM +0100, venom@sns.it wrote: > > > On Tue, 27 Jan 2004, Christoph Hellwig wrote: > > > > Yes, it does. But JFS should get the right size from the gendisk anyway. > > Or did you create the raid with the filesystem already existant? While that > > appears to work for a non-full ext2/ext3 filesystem it's not something you > > should do because it makes the filesystem internal bookkeeping wrong and > > you'll run into trouble with any filesystem sooner or later. > > > In most situation to create a new FS on a RAID1 MD is not an option. > It happens that you have to mirror a partition, maybe alarge one, and it > already had a filesystem on top of it. Then what should you do? > backup, mirror and then restore? Sometimes it is not possible this too. > Then you accept to deal with the possible problems... > If you need to mirror it - then you have an empty mirror disk ready, right? Create a degraded array on the mirror disk, then make a fs there. Then copy everything over from the original partition. After this, change the original partition to raid and add it to the other array. (It will then be updated from the copy). This approach works with all filesystems, including those that cannot be resized. Data is copied twice instead of once, but teh copying step will defragment files and you have the option of changing filesystem or take advantage of sparse files if you so wish. Helge Hafting - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/