[linux-lvm] Hardware snapshots and LVM2?

[linux-lvm] Hardware snapshots and LVM2?

[fredrik.backman]

Hi

Im doing a snapshot (hardware-based in EVA5000) of a LV 
(lvm2) and i 
wonder what is the correct way to use this snapshot? 
Problem is that 
this snapshot has the same ID as the original one. In HP-UX 
a would do a 
vgchgid on this snapshot-LV. Any help would be aprreciated.

Regards Fredrik

Re: [linux-lvm] Hardware snapshots and LVM2?

[Greg Freemyer]

On 3/21/06, fredrik.backman@nll.se <fredrik.backman@nll.se> wrote:
> Hi
>
> Im doing a snapshot (hardware-based in EVA5000) of a LV
> (lvm2) and i
> wonder what is the correct way to use this snapshot?
> Problem is that
> this snapshot has the same ID as the original one. In HP-UX
> a would do a
> vgchgid on this snapshot-LV. Any help would be aprreciated.
>
> Regards Fredrik

I think that is filesystem dependent.

If you happen to be using XFS I believe they have a mount option like
"-o nouuid".

Do a man mount.xfs to double check.

Greg
--
Greg Freemyer
The Norcross Group
Forensics for the 21st Century

Re: [linux-lvm] Hardware snapshots and LVM2?

[Nathan Scott]

On Tue, Mar 21, 2006 at 03:53:16PM -0500, Greg Freemyer wrote:
> On 3/21/06, fredrik.backman@nll.se <fredrik.backman@nll.se> wrote:
> > Hi
> >
> > Im doing a snapshot (hardware-based in EVA5000) of a LV
> > (lvm2) and i
> > wonder what is the correct way to use this snapshot?
> > Problem is that
> > this snapshot has the same ID as the original one. In HP-UX
> > a would do a
> > vgchgid on this snapshot-LV. Any help would be aprreciated.
> >
> > Regards Fredrik
> 
> I think that is filesystem dependent.
> 
> If you happen to be using XFS I believe they have a mount option like
> "-o nouuid".

If its XFS, you can either do that or change the UUID via xfs_admin(8).

> Do a man mount.xfs to double check.

Its mount(8), all the filesystems are documented together in one place.

cheers.

-- 
Nathan

Re: [linux-lvm] Hardware snapshots and LVM2?

[Mike Snitzer]

On 3/21/06, fredrik.backman@nll.se <fredrik.backman@nll.se> wrote:
> Hi
>
> Im doing a snapshot (hardware-based in EVA5000) of a LV
> (lvm2) and i
> wonder what is the correct way to use this snapshot?
> Problem is that
> this snapshot has the same ID as the original one. In HP-UX
> a would do a
> vgchgid on this snapshot-LV. Any help would be aprreciated.

You're creating snapshots of the entire block device.  As such the
snapshot device has identical LVM2 metadata as the origin device.  You
need to generate new PV, VG, LV UUIDs, modify the metadata and then
restore that modified metadata to the snapshot device (via
vgcfgbackup, vgcfgrestore).  EVMS has a decent random lvm2 UUID
generator function that can be pulled out and made to run standalone.

Mike