RELABELSCRATCH parameter supported for DEFINE and UPDATE library commands (for Virtual Tape Libraries)

Content

Virtual Tape Libraries (VTLs) maintain volume space allocation after Tivoli Storage Manager has deleted a volume and returned it to a scratch state. The VTL has no knowledge that the volume was deleted and it keeps the full size of the volume allocate. This can be extremely large depending on the devices being emulated. As a result of multiple volumes that return to scratch, the VTL can maintain their allocation size and run out of storage space.

The only way for the VTL to realize that a volume has been deleted and its space can be reallocated is to write to the beginning of the newly returned scratch volume. The VTL will then see the volume as available. Tivoli Storage Manager can relabel volumes that have just been returned to scratch if the RELABELSCRATCH parameter is specified. 

This optional parameter has been added to the DEFINE and UPDATE LIBRARY commands and is intended for use with VTLs. See the sections below for command changes.

Command Updates:

DEFINE and UPDATE LIBRARY

Syntax:

 Parameter:
RELABELSCRatchSpecifies whether the server relabels volumes that have been deleted and returned to scratch. When this parameter is set to Yes, a LABEL LIBVOLUME operation is started and the existing volume label is overwritten. This parameter is optional and intended for use with Virtual Tape Libraries (VTLs).Note: If you have both virtual and real volumes in your VTL, both types will be relabeled when this parameter is enabled. If the VTL includes real volumes, specifying this option could impact performance.
NoSpecifies that the server does not relabel volumes that are deleted and returned to scratch. This is the default value.
YesSpecifies that the server relabels volumes that are deleted and returned to scratch.
 

To determine if the RELABELSCRATCH parameter is set to Yes, you can issue the QUERY LIBRARY command.

QUERY LIBRARY

FORMAT= DETAILED updated output:

q libr D2DBSL6 f=d
ANR2017I Administrator SERVER_CONSOLE issued command: QUERY LIBRARY D2DBSL6 f=d

              Library Name: D2DBSL6
              Library Type: VTL
                    ACS Id:
          Private Category:
          Scratch Category:
     WORM Scratch Category:
          External Manager:
                    Shared: Yes
                   LanFree:
        ObeyMountRetention:
   Primary Library Manager:
                       WWN: 51402EC008836A9D
             Serial Number: ZZ001XC046
                 AutoLabel: No
              Reset Drives: Yes
           Relabel Scratch: Yes
                  ZosMedia: