Versioning partitioned data sets

If the versioning capability is going to be used, at least one versioning partitioned data set must be allocated. If you intend to use the VERCOUNT parameter on the FLMCNTRL macro to specify that two or more versions be maintained, you must specify at least one versioning partitioned data set for each group to be versioned. Otherwise, errors can occur during version retrieval. You can also choose to have a versioning partitioned data set associated with each 'group.type' to be versioned.

Table 1 shows the attributes required for the versioning partitioned data set. All attributes must be coded as shown, with the exception of LRECL, which defines the minimum LRECL allocation required for versioning. The LRECL value must be at least 259 and must be 4 bytes more than the LRECL of the largest source data set to be versioned.

Table 1. Versioning Data Set Attributes
Attribute	Description
LRECL =	The larger of 259 and the source data set's LRECL + 4
RECFM =	Variable Blocked (VB)
BLKSIZE =	At least LRECL + 4 Bytes. Use the optimal block size for your system.

The 4 bytes in the block size calculation are for MVS™ control information, specifically for the blocklength field. For example, with a blocking factor of 10 the block size would be calculated as follows:

(259 x 10) + 4 = 2594