How to Expand the ACF2 Database Clusters

Document ID : KB000027050
Last Modified Date : 14/02/2018
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Introduction:

1. Overview of process to expand the ACF2 database clusters.
2. Details and factors that influence this process.
3. Refer to Maintaining ACF2 Databases for general maintenance considerations.

Additional Information:

CA recommends that database expansion is only performed when there is no or very little ACF2 database update activity.

Summary of process:

1. Backup the active (primary) clusters
2. Delete and redefine the alternate clusters
3. Reload the alternate clusters from primary backups
4. Switch to the alternate clusters
5. Delete and redefine the primary clusters, increasing the sizes
6. Reload the new (expanded) primary clusters
7. Switch to the new (expanded) primary clusters

Instructions:

1. Backup the active (primary) clusters

  • When ready to begin this process, issue F ACF2,BACKUP at the MVS operator console.
  • This backs up the primary (or currently active) clusters to the primary backup files (or corresponding active backup files).
  • These clusters and backups may be defined in the ACFFDR, or may be specified in the ACF2 startup JCL procedure.
  • CA recommends that the primary and alternate clusters, along with their backup files, be defined in the ACFFDR, using @DDSN group names.

2. Delete and redefine alternate clusters

  •  CA supplies a sample JCL procedure in the CAIPROC library, member ACFBKUP. This JCL performs an IDCAMS delete of the alternate ACF2 clusters, redefines these clusters, and then performs an IDCAMS REPRO of the primary backup files to the redefined alternate clusters.
  • The value specified in STRING (of the GSO BACKUP record) is issued as a console command after the completion of the backup of the active ACF2 database clusters. CA recommends specifying a STRING value to start the ACFBKUP procedure (or similar JLC).
  • Ensure that the DEFINE of the alternate clusters matches the sizes of the expanded primary clusters.
  • If the STRING value is specified be aware that this will be executed after a manual backup, as well as after the automatic backup.
  • If ACFBKUP is not being used, ensure that appropriate JCL is setup ahead of time and redefines the alternate clusters.

3. Reload the alternate clusters from active (primary) backups

  • ACFBKUP provides a second step to perform an IDCAMS REPRO of the primary backups to the alternate clusters.
  • If ACFBKUP is not used, ensure that JCL is prepared ahead of time to perform this reload of the alternate clusters, and execute that JCL after redefining the alternate clusters.

       NOTE: when using the GSO BACKUP STRING to start the ACFBKUP procedure, tasks 1, 2, and 3 are effectively combined into a single task.

4. Switch to the alternate clusters

  • This can be performed as a stop and restart of ACF2. Issue the console commands:

    P ACF2
    S ACF2 ,PARM='DDSN(ALT)'

    Where ALT is the ACFFDR @DDSN name for the alternate clusters.
  • If the ACF2 clusters are not defined in the ACFFDR, then the ACF2 startup JCL requires DDNAMES for the database clusters and backup files, which have to be updated to change from the primary to the alternate clusters. In this case, predefine separate procedures and perform renames to ensure the proper JCL is started.
  • If the use of the SWITCH command is enabled (ACF2 9.0 and above), issue the command:

    F ACF2,SWITCH(ALT)

    Where ALT is the ACFFDR @DDSN name for the alternate clusters.

       NOTE: to use the SWITCH command requires the clusters to be specified in the ACFFDR, a GSO specified SWITCHKEY must be defined, and there are                 OPERCMD validation considerations. Refer to the documentation in the ACF2 System Programmer Guide.

5. Delete and redefine the primary clusters, increasing the sizes

  • CA supplies a sample JOB in the SAMPJCL library, member DEFINE. This JCL creates the primary ACF2 clusters. Use this and ACFBKUP as a model to delete and redefine the primary clusters with more space. Note that secondary allocations are allowed.

6. Reload the new (expanded) primary clusters

  • This reload may use the primary backups from step 1.
  • If there is significant update activity to the alternate clusters during this time, you may want to get a backup of the alternate clusters and use the alternate backups as input to reload the expanded primary clusters.
  • Using a procedure or job similar to ACFBKUP can combine steps 5 and 6 into a single task. Ensure that you specify the desired input.

7. The standard start uses the primary clusters.

  • If the ACF2 clusters are not defined in the ACFFDR, be sure to start the appropriate JCL.
  • If the use of the SWITCH command is enabled (ACF2 9.0 and above), issue the command:

    F ACF2,SWITCH(PRIMARY)

       NOTE: to use the SWITCH command requires a GSO specified SWITCHKEY, and there are also OPERCMD validation considerations.


NOTE: If you have the available downtime window, a simplified process would be:

1. Backup the active clusters
2. Stop ACF2: P ACF2
3. Delete, redefine the primary clusters with increased space, and reload the primary clusters using the backups
4. Start ACF2: S ACF2
5. Be sure to update the ACFBKUP procedure with the appropriate sizes

Additional reference information:

ACF2 Documentation Section: GSO Options BACKUP record, OPTS record (SWITCHKEY)

ACF2 Documentation Section: CA ACF2 Field Definition Record (ACFFDR)

ACF2 Documentation Section: Database RecoveryACFBKUP Procedure

ACF2 Documentation Section: Console Operator Commands Backup, Start, Stop, and Switch