Re: BTRFS messes up snapshot LV with origin

[Robert White <rwhite@pobox.com>]

On 11/20/2014 10:22 PM, Duncan wrote:
> But while other filesystems might allow un-UUIDs (heh, UUUIDs or U3IDs
> =:^), because they're no longer unique, requiring them to be unique just
> as the label says cannot be considered a bug.  It's simply stricter
> enforcement of the rules, which are, after all, plainly stated in the
> descriptive name.

You take "U"s away, not add them

UID = unique ID
GUID = globally unique ID
UUID = universally unique ID


And other file systems have the same issues. XFS, for example uses UUIDs 
in the same way. It just has a command to re-brand the filesystem's UUID 
which you apply to the LVM snapshot immediately after taking the 
snapshot. (problem long-since established and understood since 2009 or so.)

I don't know if this approach would work for BRFS with subvolumes.

Example Citation :: 
http://www.miljan.org/main/2009/11/16/lvm-snapshots-and-xfs/

XFS also has the nouuids mount option.

btrfs has device= mount option.

But any system with unique ids will have this identical issue when 
block-snapshot support is added underneath.

-- Rob.