Issue

• When thin_dump is run against the file below error messages are seen:

[root@vmhost01 meta]# thin_dump /tmp/meta
<superblock uuid="" time="510" transaction="943" data_block_size="2048" nr_data_blocks="2097152">
metadata contains errors (run thin_check for details).
perhaps you wanted to run with --repair

• When run the program with '--repair' the only XML produced is this:

[root@vmhost01 meta]# thin_dump -r /tmp/meta
<superblock uuid="" time="510" transaction="943" data_block_size="2048" nr_data_blocks="2097152">
</superblock>

• When run a thin_check below messages are seen:

# thin_check /tmp/meta
examining superblock
examining devices tree
examining mapping tree
  missing all mappings for devices: [12501, -]
    invalid key invalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid keyinvalid key..
invalid key invalid keyinvalid keyinvalid key

• 'repair' operation apparently results in a bare superblock with no actual devices at all being found/rendered.

• why these tools aren't apparently working on this running system, how to use them, and what steps can be taken to backup thin provisioned metadata?