[linux-lvm] File-system uuid on LVM snapshot

[Rajesh Joseph]

Thanks Zdenek for the quick reply.

We are using thin volumes and thin snapshot, but we need all or most snapshots active. Therefore we are enabling the snapshot by-default.
As you suggested we can have a workaround to mount those snapshot volumes by using 'nouuid' option.
But the problem is in most of our use case the origin volume is mounted using the /etc/fstab. And here the mount entry is made using UUID.
So in some cases instead of Origin volume the snapshot volume get mounted.

Thanks & Regards,
Rajesh

----- Original Message -----
> From: "Zdenek Kabelac" <zkabelac at redhat.com>
> To: linux-lvm at redhat.com
> Sent: Thursday, June 5, 2014 2:49:51 PM
> Subject: Re: [linux-lvm] File-system uuid on LVM snapshot
> 
> Dne 5.6.2014 10:26, Rajesh Joseph napsal(a):
> > Hi all,
> >
> > Origin volume and snapshot volume share the same file-system UUID. So after
> > the snapshot we fix the uuid by running xfs_admin or tune2fs.
> > Do you have any recommendation or best practice in this regard?
> >
> 
> 
> With thin pools and thin volumes - snapshot of thin volume is now created
> 'inactive' and it's skipped from default activation  (you could always
> override skip with -K  i.e. : lvchange -ay -K vg/mythinsnap)
> 
> So with thins you should mostly have only a single volume active with the FS
> UUID.  If you happen to have multiple volumes active and you need to mount
> xfs
> filesystem  - use  'nouuid' (and eventually  norecovery for read-only
> activated snapshots)  mount options.
> 
> For old-snapshosts - all volumes need to be available/active - so you need to
> use 'nouuid' option always.
> 
> I don't see much point in changing  FS UUID on your snapshot - unless of
> course you plan to use snapshots as different volumes with just a 'single'
> starting point  (i.e. preinstalled tree of files)
> 
> Regards
> 
> Zdenek
> 
> 
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