Sharing tape drives between partitions

You can assign a stand-alone tape device to a partition or leave a tape device unassigned and share it between partitions.

You can choose whether you want your stand-alone tape device assigned to a partition when the tape device is varied on. Assigning a tape device reserves the tape device specifically for one partition. If it is not assigned, then multiple partitions can share the device. For a device to be shared it either needs to have multiple ports or be connected via a SAN.

Note: If a SAS tape or library device is shared between partitions, IPLing the adapter or partition will disrupt any operation using the device from the other partition, even if the device is assigned to the other partition.
To assign a tape device to a system, do the following steps.
  1. Use the Work with Device Description (WRKDEVD *TAP) command to work with the tape device description.
  2. Select 8 (Work with status) to view the current device status. If the device is varied on it will need to be varied off before the assign value can be changed. Use option 2 (Vary off) to vary off the tape device if necessary.
  3. Select 2 (Change) for the tape device you want to use and enter *YES for the Assign device at vary on parameter.
  4. Select 8 (Work with Status) and use option 1 (Vary on) to vary on the tape device.

If the tape device is being used by another partition, a message is displayed that indicates the tape device is assigned elsewhere. The tape device must be varied off at the other partition before it can be varied on at a new partition.

To leave a tape device unassigned, do the following steps.
  1. Use the Work with Device Description ( WRKDEVD *TAP) command to work with the tape device description.
  2. Select 8 (Work with status) to view the current device status. If the device is varied on it will need to be varied off before the assign value can be changed. Use option 2 (Vary off) to vary off the tape device if necessary.
  3. Select 2 (Change) for the tape device you want to use and enter *NO for the Assign device at vary on parameter.
  4. Select 8 (Work with status) and use option 1 (Vary on) to vary on the tape device.

An unassigned tape drive can be in the varied on state on multiple partitions at the same time, but only one partition can be actively using the device.