When updating volumes containing a non-indexed VTOC keep the following considerations in mind:

• Restoring a Volume from a Dump Tape: There are no operational requirements if you change the volume serial number or do a partial restore that does not modify the VTOC. If you do a restore and change the VTOC size without changing the volume serial number, the system can automatically update the UCB with the new VTOC location and new volume serial number following a Restore or Copy Volume operation if you have the REFUCB function enabled. To enable this function, do one of the following:
  • Specifiy ENABLE(REFUCB) in the DEVSUPxx parmlib member
  • Issue the MODIFY command as follows:

    F DEVMAN,ENABLE(REFUCB)

  If you do not enable REFUCB, you cannot restore on a volume with an indexed VTOC. In that case, you must vary the volume offline after it is restored.
• Copying a Volume: There are no operational requirements if you change the volume serial number or do not modify the VTOC of the receiving volume. If you do a copy and change the VTOC size without changing the volume serial number, you must vary the volume offline after it is copied. Do not attempt to copy from a volume with an indexed VTOC.
• Shared DASD Considerations:In shared DASD environments, if the VTOC index is relocated or the volume is changed from indexed VTOC to nonindexed VTOC or from nonindexed VTOC to indexed VTOC, it generally is advisable to vary the device offline to the sharing system or systems before beginning the operation. However it is not necessary to vary the volume offline on other systems in the same sysplex z/OS® Version 1 Release 5 or higher using ICKDSF release 17.