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Administrator's Guide


Understanding Tivoli Storage Manager Server Tape Processing

To integrate TSM tapes into your tape library, you need to understand how the server uses tapes. You can either predefine tape volumes to a storage pool or specify that TSM dynamically acquire scratch tape volumes, as needed.

TSM automatically reuses predefined tape volumes when all space on a volume becomes available, such as when reclamation occurs. When scratch tapes become empty, TSM dynamically deletes the volumes from the storage pool and returns the tapes to a scratch pool.

Processing Tapes

TSM uses the normal tape mounting procedures of MVS(TM) to mount, dismount, and process tapes. If you have a tape management system installed, you can use that system to manage the server tape handling as you would manage any other tape user. See Defining Tivoli Storage Manager to Your Tape Management System for information.

You can also protect TSM tapes from being used by other applications by setting the expiration date to 99365 for the device class. See File Expiration Date for information on setting an expiration date.

In addition, consider using RACF(R) to protect predefined volumes from unauthorized users. See Protection Status for information on setting protection for tape volumes.

The tape management system can be signalled when a tape has been deleted from the TSM server database through a tape deletion exit. See Setting Up Tape Installation-Wide Exits for information on using the deletion exit.

Understanding How the Server Selects and Handles Tapes

To effectively manage tape operations, you need to understand how the server selects tapes, requests tape mounts, and maintains information on the condition of tapes. See How the Server Groups Files before Storing for information on how the server selects tapes based on your storage pool definitions.

Controlling Tape Mounts

You can define how long a tape can sit idle on a drive. When defining a device class, you can define how long the server allows a mounted tape to sit idle on the tape drive with the MOUNTRETENTION parameter.

Both the MOUNTWAIT and MOUNTRETENTION parameters may be changed when updating the device class. You can change the other tape options by updating the server options file.

Requesting Tapes

The server requests tapes by using the standard MVS services for mounting tapes. Handle the server mount requests as you would handle any other tape mount request.

Maintaining Information on Tape Condition

If the server cannot process a tape correctly, it records an error state for the tape so that it knows the tape cannot be processed correctly. General errors are recorded in the activity log; severe errors are recorded in the error log.

The two error states are I/O error and unavailable.

A volume is placed in I/O error state whenever the server receives a permanent I/O error when processing the tape. A tape in I/O error is no longer written to although the tape can be mounted when a file needs to be retrieved from the tape.

A volume is placed in unavailable state when the server has detected the volume has become corrupted, when the CANCEL REQUEST PERMANENT command has been issued to cancel a mount request for the volume, or when the volume status is changed to unavailable with the UPDATE VOLUME command. A tape in unavailable error state is no longer requested by the server, either for writing or reading.

You can use the QUERY VOLUME command to show the error states of volumes. To try to recover files on unavailable volumes, use the following procedure:

  1. Use the QUERY CONTENT command to determine what files should be on the tape. If the files are out-of-date or otherwise not needed, proceed to step 6.
  2. Use the UPDATE VOLUME command to make the tape available for mounting by setting ACCESS to read-only.
  3. Try to read the tape. If the tape can be read without error, it might have been inadvertently marked as unavailable, as a result of a CANCEL REQUEST PERMANENT command. Ensure the volume status is changed to read-only or read-write, and do not proceed with the following steps.
  4. Use the MOVE DATA command to try to recover the files that you still need.
  5. If the MOVE DATA command does not work, use the AUDIT VOLUME command to synchronize the database with the readable contents of the tape. Unreadable files are deleted from the database, and you cannot recover them from the tape.
  6. Use the DELETE VOLUME command to delete the volume from the server's database. If important files are lost, inform the affected users that their files are no longer available.


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