[linux-lvm] [Q]XFS + LVM Snapshot?

[linux-lvm] [Q]XFS + LVM Snapshot?

[Sean Oh]

Hi,

Kernel: 2.4.15-pre4 with XFS patch ( linux-2.4-xfs CVS tree from SGI site)
LVM: current - LVM CVS

Patches applied: linux-2.4.11-VFS-lock.patch from LVM CVS


I have tried to test the LVM snapshot feature with XFS and encountered the following problem.

*I can not mount the original FS and snapshot FS at the same time. If I unmount the origianal XFS FS and then mount the snapshot FS, it works, tough.

Is there any patches that I missed??

Thanks in Advance.

Re: [linux-lvm] [Q]XFS + LVM Snapshot?

[Andreas Dilger]

On Nov 18, 2001  02:59 +0900, Sean Oh wrote:
> Kernel: 2.4.15-pre4 with XFS patch ( linux-2.4-xfs CVS tree from SGI site)
> LVM: current - LVM CVS
> 
> Patches applied: linux-2.4.11-VFS-lock.patch from LVM CVS
> 
> *I can not mount the original FS and snapshot FS at the same time. If
> I unmount the origianal XFS FS and then mount the snapshot FS, it works,
> tough.

Yes, you need an XFS patch which does something with the filesystem UUID
in the snapshot.  XFS has a feature which prevents the same filesystem
from being mounted more than once.

What they do to fix this is to create writable snapshots.  What I would
rather they do is in the "duplicate UUID detection" code, allow mounting
of devices which are on read-only media (e.g. a snapshot).

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

Re: [linux-lvm] [Q]XFS + LVM Snapshot?

[Sean Oh]

Sorry, but where can I find that patch?

Thanks again for your reply.

----- Original Message ----- 
From: "Andreas Dilger" <adilger@turbolabs.com>
To: "Sean Oh" <oh@linuxsecurity.co.kr>
Cc: <linux-lvm@sistina.com>
Sent: Sunday, November 18, 2001 7:22 AM
Subject: Re: [linux-lvm] [Q]XFS + LVM Snapshot?


> On Nov 18, 2001  02:59 +0900, Sean Oh wrote:
> > Kernel: 2.4.15-pre4 with XFS patch ( linux-2.4-xfs CVS tree from SGI site)
> > LVM: current - LVM CVS
> > 
> > Patches applied: linux-2.4.11-VFS-lock.patch from LVM CVS
> > 
> > *I can not mount the original FS and snapshot FS at the same time. If
> > I unmount the origianal XFS FS and then mount the snapshot FS, it works,
> > tough.
> 
> Yes, you need an XFS patch which does something with the filesystem UUID
> in the snapshot.  XFS has a feature which prevents the same filesystem
> from being mounted more than once.
> 
> What they do to fix this is to create writable snapshots.  What I would
> rather they do is in the "duplicate UUID detection" code, allow mounting
> of devices which are on read-only media (e.g. a snapshot).
> 
> Cheers, Andreas
> --
> Andreas Dilger
> http://sourceforge.net/projects/ext2resize/
> http://www-mddsp.enel.ucalgary.ca/People/adilger/
> 
> 
> _______________________________________________
> 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
> 

Re: [linux-lvm] [Q]XFS + LVM Snapshot?

[Patrick Caulfield]

On Sun, Nov 18, 2001 at 02:59:53AM +0900, Sean Oh wrote:
> Hi,
> 
> Kernel: 2.4.15-pre4 with XFS patch ( linux-2.4-xfs CVS tree from SGI site)
> LVM: current - LVM CVS
> 
> Patches applied: linux-2.4.11-VFS-lock.patch from LVM CVS
> 
> 
> I have tried to test the LVM snapshot feature with XFS and encountered the following problem.
> 
> *I can not mount the original FS and snapshot FS at the same time. If I unmount the origianal XFS FS and then mount the snapshot FS, it works, tough.

If you have fairly recent XFS code you should be able to mount the snapshot with
the -onouuid,norecovery options.

patrick