Defining a page set to be larger than 4GB

WebSphere MQ can use a page set up to 64GB in size, provided the data set is defined with 'extended addressability' to VSAM. Extended addressability is an attribute which is conferred by an SMS data class. In the examples below, the management class 'EXTENDED' is defined to SMS with 'Extended addressability'. If your existing page set is not currently defined as having extended addressability, use the following method to migrate to an extended addressability format data set.

1. Stop the queue manager.

2. Use Access Method Services to rename the existing page set.

3. Define a destination page set, the same size as the existing page set, but with DATACLASS(EXTENDED).

4. Use Access Method Services REPRO to copy the contents of the existing page set to the destination page set.

5. Restart the queue manager.

6. Alter the page set to use system expansion, to allow it to continue growing beyond its current allocation.

The following JCL shows example Access Method Services commands:

//S1        EXEC PGM=IDCAMS 
//SYSPRINT  DD   SYSOUT=* 
//SYSIN     DD   * 
  ALTER 'VICY.CSQ1.PAGE01' - 
         NEWNAME('VICY.CSQ1.PAGE01.OLD') 
  ALTER 'VICY.CSQ1.PAGE01.DATA' - 
         NEWNAME('VICY.CSQ1.PAGE01.DATA.OLD') 
  DEFINE CLUSTER (NAME('VICY.CSQ1.PAGE01') - 
         MODEL('VICY.CSQ1.PAGE01.OLD') - 
         DATACLASS(EXTENDED)) 
  REPRO  INDATASET('VICY.CSQ1.PAGE01.OLD') - 
         OUTDATASET('VICY.CSQ1.PAGE01') 
/*