VTL offline and backups unable to run (4047471)

Symptoms:

VTL is offline (marked red in device management), backups are unable to run and are stopping on waiting for media, diagnosing the jobs shows only 'vtl offline'.
Attempting to remove and re-add the VTL gives the error 'call back from unknown source' .
Netvault attempts to automatically re-add library.
All entries for the VTL are correct in the diskdevices.cfg file.


Reason:
The Netvault database device tree is corrupted due to the disk filling up with runaway trace.

1. Stop Netvault
2. Check that trace is disabled
3. Delete the old trace files and the 2 device tree files in /index/devicetree and records/devicetree
4. Restart Netvault
5. Manually readd devices

If problems still occur a full restore of the Netvault database may be required.