Dynamically adding tape devices to MIA's control

Document ID : KB000049763
Last Modified Date : 14/02/2018
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Description:

The focus of this document is providing a procedure for dynamically adding tape devices for MIA to manage using z/OS ACTIVATE.

Solution:

Resynchronization is the MIA process which can dynamically change the devices defined to MIA for management. You can add tape devices for MIA to manage either by issuing the MIA RESYNCH command (for devices already genned) or by performing a z/OS ACTIVATE.

If you are adding existing tape devices (currently defined to z/OS) to MIA device management, then you will manually issue the MIA RESYNCH command. The MIA RESYNCH command is documented in the MIM Statement and Command Reference, so the complete description and use of the RESYNCH command will not be duplicated here. All MIM manuals are available for viewing online or for downloading as a PDF file.

If you will be performing a z/OS ACTIVATE to add tape devices, then MIA will detect the ACTIVATE and automatically perform a resynchronization. This resynchronization triggers the same internal process that occurs when an MIA RESYNCH command is processed. The rest of this document describes the process of setting up MIA for resynchronization prior to performing a z/OS ACTIVATE. A separate document will discuss using z/OS ACTIVATE to delete devices from MIA management.

Here is a summary of the steps when adding devices to MIA management using z/OS ACTIVATE:

  1. Verify the current MIA initialization settings for managing tape devices.
  2. Verify the current MIA command settings for resynchronization.
  3. Decide how MIA will manage tape devices after resynchronization and set the appropriate values.
  4. Initiate z/OS ACTIVE.

  1. Verify the current MIA initialization settings for managing tape devices.

    To begin, you should be aware of how you currently instruct MIA to manage tape devices on the MIMINIT initialization statement. You can verify this by issuing MIM command DISPLAY MIM INIT. The command response will identify the values currently in effect for the DEVCLASS and DEVLIST initialization parameters. DEVCLASS can specify TAPE or NONE. DEVLIST can specify NONE or it can specify a MIMPARMS member name in which device definition statements have been coded.

    Specifying DEVCLASS=TAPE instructs MIA to manage the entire class of tape devices. Using DEVLIST to specify a MIMPARMS member provides MIA with a list of select tape devices to manage. The default member name, and the name by which we commonly refer to the DEVLIST member, is MIMUNITS but you can use any valid PDS member name. Most customers will specify 1 of the following 2 options:

    1. DEVCLASS=TAPE and DEVLIST=NONE
    2. DEVCLASS=NONE and DEVLIST=membername

    It is very uncommon to specify both DEVCLASS=TAPE and DEVLIST=membername, but is typically done to manage all tape devices while using a device list to assign global names to devices.


  2. Verify the current MIA command settings for resynchronization.

    Next, verify the parameters specified on the MIA settable option called RESYNCH. Do this by issuing MIA command DISPLAY GTAF OPTIONS. Part of the output will look similar to this:

    • CURRENT RESYNCH OPTIONS:
      DEVCLASS=NONE      DEVLIST=MIAUNITS      COMMANDS=NONE
      SAMEDEVS=NO

    The RESYNCH options will be used by MIA when either manual (RESYNCH command) or an automatic resynchronization occurs. To briefly describe the RESYNCH options:

    • DEVCLASS and DEVLIST:
      These parameters have the same meaning here as when specified on the MIMINIT statement.

    • SAMEDEVS:
      This option specifies whether you want MIA to continue managing only the same devices it was managing prior to resynchronization. Assuming that you want MIA to start managing the devices being added, specify the default of NO for this option. Otherwise, specify YES and MIA will not start to manage the new devices even if you specify DEVCLASS=TAPE or you specify a MIMUNITS member that includes the new devices.

    • COMMANDS:
      This parameter identifies a MIMPARMS member that can be used to issue commands as part of the resynchronization process. The COMMANDS member is typically a single-use member that contains MIA VARY commands that are processed when resynchronization completes. This COMMANDS member is not intended to be the same member as your existing MIMCMNDS or MIMSYNCH members.


  3. Decide how MIA will manage tape devices after resynchronization and set the appropriate values.

    Below are the options that you can set for when MIA performs automatic resynchronization. You would issue the corresponding SET command and then use MIA command DISPLAY GTA OPT to verify your settings before initiating z/OS ACTIVATE.

    For the options where you want MIA to start managing the new devices and you are specifying a DEVLIST member name, you can update the member with the addresses of the new devices before starting the z/OS ACTIVATE. The member can be your existing MIMUNITS member or you can create a new MIMPARMS member.

    All of the options below are shown with COMMANDS=NONE specified. For the options where you want MIA to immediately start managing new devices, you can specify a member name instead of COMMANDS=NONE if you want MIA to issue VARY ONLINE commands for the new devices. The COMMANDS member with the MIA VARY commands must exist in MIMPARMS prior to starting the z/OS ACTIVATE.

    Determine the option which is applicable to you before initiating z/OS ACTIVATE:

    1. I use DEVCLASS=TAPE, I want to continue using DEVCLASS=TAPE, and I want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=TAPE,DEVLIST=NONE,COMMANDS=NONE,SAMEDEVS=NO)

    2. I use DEVCLASS=TAPE, I want to continue using DEVCLASS=TAPE, and I don't want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=TAPE,DEVLIST=NONE,COMMANDS=NONE,SAMEDEVS=YES)

    3. I use DEVCLASS=TAPE, I don't want to continue using DEVCLASS=TAPE, and I want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=NONE,DEVLIST=member,COMMANDS=NONE,SAMEDEVS=NO)

    4. I use DEVCLASS=TAPE, I don't want to continue using DEVCLASS=TAPE, and I don't want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=NONE,DEVLIST=member,COMMANDS=NONE,SAMEDEVS=YES)

    5. I use a DEVLIST member, I want to continue using a DEVLIST member, and I want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=NONE,DEVLIST=member,COMMANDS=NONE,SAMEDEVS=NO)

    6. I use a DEVLIST member, I want to continue using a DEVLIST member, and I don't want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=NONE,DEVLIST=member,COMMANDS=NONE,SAMEDEVS=YES)

    7. I use a DEVLIST member, I don't want to continue using a DEVLIST member, and I want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=TAPE,DEVLIST=NONE,COMMANDS=NONE,SAMEDEVS=NO)

    8. I use a DEVLIST member, I don't want to continue using a DEVLIST member, and I don't want MIA to manage the new tape devices.
      - Use this MIM command: F MIM,RESYNCH=(DEVCLASS=TAPE,DEVLIST=NONE,COMMANDS=NONE,SAMEDEVS=YES)


  4. Initiate z/OS ACTIVE.

    Once you issue the appropriate SET RESYNCH command and verify the settings with the D GTA OPT command, you can then initiate the z/OS ACTIVATE.

    Reminder - z/OS ACTIVATE is a local process that affects devices only on the system where it executes. The MIA resynchronization process is also local in scope, regardless of whether resynchronization occurs automatically as a result of z/OS ACTIVATE or is initiated manually as a result of the MIA RESYNCH command.

    Once the z/OS ACTIVATE and the MIA resynchronization complete, you should verify whether your MIMUNITS member that is specified on the MIMINIT statement is the correct member name and includes the tape devices which were just added if you want MIA to manage the devices after the next MIA restart. You may also need to verify whether the added tape devices should be included in any VARY ONLINE commands that you specify in the MIMSYNCH member.

    The original documentation source for the MIA resynchronization process is the MIA Programming Guide. For additional information on MIA resynchronization, refer to Chapter 3: 'Advanced Topics' in the section called "How You Dynamically Change Which Devices Are Managed".