Expanding Space Allocation of ACF2 databases

Products

• ACF2
• ACF2 - z/OS
• ACF2 - MISC

Issue/Introduction

This article explains the process to expand the Space Allocation of ACF2 databases when getting one or more out of space errors when adding or modifying database records in ACF2.

Resolution

WARNING: Best practice is that database space allocation expansion is only performed when there is very little to no ACF2 database update activity.
The use of the SWITCH command is the preferred method for switching databases.

Table of Contents

• 1. Backup the active (primary) clusters
• 2. Delete and redefine alternate clusters
• 3. Reload the alternate clusters from active (primary) backups
• 4. Switch to the alternate clusters
• 5. Delete and redefine the primary clusters, increasing the space allocation.
• 6. Reload the new (expanded) primary clusters
• 7. Switch to the new (expanded) primary clusters. The standard start uses the primary clusters.

Step 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.
• It is recommended that the primary and alternate clusters, along with their backup files, be defined in the ACFFDR, using @DDSN group names.

Step 2. Delete and redefine alternate clusters

• ACF2 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.
  It is recommended to specify a STRING value to start the ACFBKUP procedure (or similar JCL).
• Ensure that the DEFINE of the alternate clusters matches the sizes of the 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 set up ahead of time and redefines the alternate clusters.

Step 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.

Step 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)'
  
  WARNING: when issuing the start command, ensure that the correct SYSID is specified if normal startup uses a different sysid  
  than the smf sysid.
  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, issue the command:
  
  F ACF2,SWITCH(ALT)
  
  Where ALT is the ACFFDR @DDSN name for the alternate clusters.

Step 5. Delete and redefine the primary clusters, increasing the space allocation.

• ACF2 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.

Step 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.

 

Step 7. Switch to the new (expanded) primary clusters. The standard start uses the primary clusters.

• There are two methods to start using the new primary clusters - stop and start of ACF2  or issue the SWITCH command.  
  
  
• This can be performed as a stop and restart of ACF2. Issue the console commands:
  
  P ACF2
  S ACF2 
  
  WARNING: when issuing the start command, ensure that the correct SYSID is specified if normal startup uses a different sysid  
  than the smf sysid.
  
  
• 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 alternate to the primary 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, issue the command:
  
  F ACF2,SWITCH(PRIMARY)
  
  Where PRIMARY is the ACFFDR @DDSN name for the primary clusters.

NOTE 1:

• 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.
• The initial and alternate databases should all have the same record size for rules and infostg databases to use the SWITCH command..
  If you wish to switch to non-equivalent databases, (e.g. new record size is increased) you must stop and restart ACF2.
  
    

NOTE 2: 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.
   
   WARNING: when issuing the start command, ensure that the correct SYSID is specified if normal startup uses a different sysid  
   than the smf sysid.

Additional Information

See the following guides in the ACF2 Documentation:

• GSO Options BACKUP record, OPTS record (SWITCHKEY)
• Field Definition Records (ACFFDR)
• Database RecoveryACFBKUP Procedure
• Console Operator Commands Backup, Start, Stop, and Switch