Advanced Topics › How You Activate Features of New Releases Dynamically

How You Activate Features of New Releases Dynamically

Although we recommend that all systems in a CA MIM complex run at the same release, there may be times when multiple releases of CA MIM are active in the same control file complex, such as when migrating to a new release.

When your complex is made up of systems running with different releases of CA MIM, you can use the CA MIM compatibility level specification to control the enabling of selected features in the complex. The compatibility level specification permits different releases of CA MIM to co-exist in the same control file complex. It controls the activation or suppression of features that, to function properly, must have all systems in the CA MIM complex participating at the same release.

You can specify the compatibility level using the following:

• The MIMINIT COMPATLEVEL statement, which you specify in the MIMINIT member of the MIMPARMS data set
• The ACTIVATE COMPATLEVEL command, which you issue to dynamically change the COMPATLEVEL of the complex

The MIMINIT COMPATLEVEL statement denotes the level at which the CA MIM complex operates, regardless of the release of the individual systems that make up the complex. The COMPATLEVEL value must be the same on all systems in the CA MIM complex.

Example: COMPATLEVEL

• Starting CA MIM r1.8 on a system that will be joining an existing CA MIM r11.7 MIMplex that is currently running with COMPATLEVEL=11.7, assume the following:
  • SYSA - running CA MIM r11.7 at COMPATLEVEL=11.7
  • SYSB - running CA MIM r11.7 at COMPATLEVEL=11.7
  • SYSC - running CA MIM r11.7 at COMPATLEVEL=11.7

  Assuming you want to start CA MIM r11.8 on SYSC, the process would be as follows

  1. Stop the CA MIM r11.7 task on SYSC.
  2. Start CA MIM r11.8 task on SYSC with COMPATLEVEL=11.7 specified in MIMINIT.

  CA MIM r11.8 on SYSC then joins the existing COMPATLEVEL=11.7 MIMplex (SYSA and SYSB) without any errors.

  Eventually, you wish to roll CA MIM r11.8 out to SYSA and SYSB. You would do the following:

  1. Stop CA MIM r11.7 task on SYSB.

  2. Start CA MIM r11.8 task on SYSB with COMPATLEVEL=11.7 specified in MIMINIT.

  3. Stop CA MIM r11.7 task on SYSA.

  4. Start CA MIM r11.8 task on SYSA with COMPATLEVEL=11.7 specified in MIMINIT

  At this point CA MIM r11.8 would be running on all three systems, but at COMPATLEVEL=11.6. To move to COMPATLEVEL=11.7 (without formatting MIM control or checkpoint files which require a global shutdown), do the following:

  1. Issue the MIM following command on any single system in the MIMplex:

  2. ACTIVATE COMPATLEVEL=11.8

  3. COMPATLEVEL=11.8 is activated, as indicated by the MIM0621I message.

  Update MIMINIT member in the MIM parmlib so that COMPAT=11.7 is changed to COMPAT=11.8

  You cannot specify COMPATLEVEL=11.8 on any CA MIM statement or command until all systems in the MIMplex are running CA MIM r11.8 code.

• In this example, assume the following
  • CA MIM r11.8 is up and running on SYSA and SYSB and at COMPATLEVEL=11.7.
  • SYSC is currently down and FREED.

  Because the ACTIVATE COMPATEVEL command expects all systems coded on the DEFSYS statement to be active at the time the command is entered, you need to use the FORCE option on the ACTIVATE command.

  For example, if you entered the ACTIVATE COMPATLEVEL command without the FORCE option, you would see the following messages:

  F MIM,ACTIVATE COMPATLEVEL=11.8
  MIM0067 COMMAND ACTIVATE
  MIM0628E ACTIVATE command aborted; all defined systems not active      
  

  CA MIM rejected the command, because CA MIM is not active on SYSC. You need to append the FORCE operand:

  F MIM,ACTIVATE COMPATLEVEL=(11.8,FORCE)
  MIM0067 COMMAND ACTIVATE
  MIM0616I ACTIVATE COMPATLEVEL=11.80 has been scheduled MIM0619I COMPATLEVEL 11.80 accepted
  MIM0620I COMPATLEVEL 11.80 activation in progress
  MIM0621I COMPATLEVEL 11.80 activation complete   
  

  The next time CA MIM is started on SYSC, start CA MIM r11.8 with COMPATLEVEL=11.8. If you start CA MIM r11.7 on SYSC with COMPATLEVEL=11.7, it abends with a U0040 during startup because the COMPATEVEL value will be different. If you try to start CA MIM r11.7 with COMPATLEVEL=11.8, it will also abend during startup because CA MIM r11.7 does not recognize the value of 11.8 on the COMPATLEVEL statement.

  The dynamic activation of compatibility levels supports:

  • Forward and backward activation of COMPATLEVEL specifications

    However, it is possible that a backward activation of a COMPATLEVEL will be denied. For example, if the CA MIM complex has exploited a new feature that cannot be converted back to a previous COMPATLEVEL, the dynamic activation will fail. In this case, the only recourse to change back to the COMPATLEVEL in question is to FORMAT start the control file, using the desired MIMINIT COMPATLEVEL specification.

  • Changing only one COMPATLEVEL level at a time

    For example, you can ACTIVATE directly from COMPATLEVEL 11.7 to 11.8. However, you cannot activate directly from COMPATLEVEL 11.6 to 11.8. To change the COMPATLEVEL from 11.6 to 11.8, you must first activate from COMPATLEVEL 4.6 to 11.6 and then activate from COMPATLEVEL 11.7 to 11.8. This restriction is true for both forward and backward activation.

Notes:

• The default value for the MIMINIT COMPATLEVEL statement is the current release. For example, if the COMPATLEVEL statement is not hard-coded in the init member, and CA MIM r11.8 is started, then the current COMPATLEVEL will be 11.8.
• You can verify the current COMPATLEVEL by entering the DISPLAY MIM INIT command.
• You can verify the current release and service level with the DISPLAY FAC command.
• Most customers prefer to “roll-out” a new MIM release one system at a time and use the ACTIVATE COMPATLEVEL command after all systems have been upgraded. However, you can choose to change the COMPATLEVEL in the init member, do a global MIM shutdown, then restart MIM on all systems with a control file format (and a checkpoint file format if used). This method eliminates the need to use the ACTIVATE COMPATLEVEL command.
• MIM 11.8 supports COMPATLEVEL= 11.8, 11.7 and 11.6.

  Note: 11.6 support is only provided for users upgrading from 11.6 to 11.8.

• The ACTIVATE command is a global command, so it needs to be entered on only one system, not all systems.
• Updating the COMPATLEVEL parameter to the current release allows new features to become active. To see which new features become available when COMPATELVEL is updated, see the Release Notes.
• During startup, CA MIM compares the COMPATLEVEL in the init member (or defaulted value) and compares it with the value in the MIM control file. If they are not the same, CA MIM issues a MIM0026E message and abends with a U0040 RC=95.