From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 25 Jul 2001 21:44:51 +0200 From: "Heinz J . Mauelshagen" Subject: Re: [linux-lvm] Reiserfs, 2.4.7, snapshots w/ 0.9 Message-ID: <20010725214451.B27765@sistina.com> References: <20010725103640.J5363@unirez.com> Mime-Version: 1.0 In-Reply-To: <20010725103640.J5363@unirez.com>; from mark@unirez.com on Wed, Jul 25, 2001 at 10:36:40AM -0500 Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@sistina.com Mark, Chris Mason implemented an interface between the VFS and LVM, which is defined by 2 new functions VFS functions. They have to be supported in the filesystem itself in order to flush the journal and lock the filesystem for I/O, get back to LVM so that it can activate the prepared snapshot. LVM unlocks the filesystem after this. You pay a (small) I/O penalty for the journal flush. Because those functions are not in vanilla, you still need to patch the kernel with the linux-2.4.X-VFS-lock-patch contained in the LVM distribution :-( That patch will enable the above feature after a kernel recompile/reboot. On Wed, Jul 25, 2001 at 10:36:40AM -0500, Mark Bainter wrote: > I'm using LVM on a couple of our production systems, and I'm very > happy with it. It's been working very well for us. However, we > have a very large database and backing it up has become problematic. > > So, naturally, I began looking into using LVM's snapshot feature. > The filesystem the database rests on is a reiserfs partition. > Creating the snapshot volume (acc to the directions in the howto) > works fine, but when I try to actually mount it I get: > > $ sudo mount -t reiserfs -oro /dev/main/db_backup /mnt/dbbackup > mount: wrong fs type, bad option, bad superblock on /dev/main/db_backup, > or too many mounted file systems > > checking dmesg reveals: > reiserfs: checking transaction log (device 3a:04) ... > clm-2076: device is readonly, unable to replay log > Replay Failure, unable to mount > reiserfs_read_super: unable to initialize journal space > > Ok, so I did some searching and found some people back in the first > part of this year had a similar problems but none of the solutions > really applied to me fwict. They all appeared to be using a > previous version of the kernel, or of the lvm code. I looked through > the changelog and did see a few notations of fixes since 0.9 related > to the snapshot code. But, I'm kind of wary about putting a beta > on my production systems with something this critical, w/out knowing > for sure that it will fix the problem. > > So, is the problem in lvm? reiserfs? Or is it just me? Is there > any other information I can give that might be helpfull in figuring > out the problem? Just let me know. > > TIA > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html -- Regards, Heinz -- The LVM Guy -- *** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them *** =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Heinz Mauelshagen Sistina Software Inc. Senior Consultant/Developer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@Sistina.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-