Solving Tape Device Allocation Problems

Document ID : KB000048080
Last Modified Date : 14/02/2018
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SCOPE:

Problems or delays in MVS tape allocation greatly affect MIA's ability to manage devices. For a number of years, customers from all ranges of sites have called in and reported these issues and asked the question: "How can we resolve these issues faster".

SOLUTION:

The MIA Programming Guide includes a Troubleshooting section which flow charts the necessary steps to take during these types of reported events in order to identify, diagnose, and resolve the following documented delay events:

  • Tape Device Allocation Problems
  • Delay Detection and Notification *
  • Tape Device Allocation Recovery Problems
  • Tape Device Preferencing Problems
  • Tape Device Dual Allocation Problems
    • '*' Indicates feature available with release 12.0 and above.

These sections also provide details on how MIA functions with MVS events, such as: HCD Activates, MVS Allocation Recovery, and Dual Allocation.

ADDITIONAL TOOLS:

Some highlighted features made available to customers running release 12.0 (COMPATLEVEL=12.0) and higher include the following:

  • Delay Detection and Notification (or D.D.N)

    This feature continually collects global tape device allocation information that is used to diagnose MIMplex wide tape device allocation delay problems. When a problem is detected, an optional warning is generated - a must for any site that needs to quickly identify and resolve delays in tape allocation.

  • ANALYZE TAPEDELAY Command

    The ANALYZE TAPEDELAY command provides a way for users to request global tape allocation delay information. When issued, this command analyzes tape allocations occurring in the MIMplex and provides a display to assist users in handling tape allocation delays.

  • Device Exclusion:

    The CA MIM Device Exclusion feature allows users to exclude specific tape devices from the CA MIM management. Excluding a tape device causes CA MIA to ignore the device, causing the device activity to be unserialized with the rest of the MIAplex.

    This is a great benefit for customers who run DEVCLASS=TAPE but have some devices they wish to not include in MIA management. Please see the DEVEXCL= parameter, which was added to the MIMINIT statement and the RESYNCH command.

Please see the MIA Programming Guide and MIM Release Notes for more information.