Global resource serialization can work well in a JES2 environment because it can replace job scheduling as a method of preserving the integrity of the data on shared DASD volumes. All of the considerations on temporary data sets and TSO/E, however, apply to a JES2 environment, and there is also an additional and important consideration.

Handling the reserve for the checkpoint data set in a JES2 multi-access spool configuration is a particularly critical decision. See z/OS JES2 Initialization and Tuning Guide for more information.

The location of the checkpoint data set, however, is another factor that affects your decision. There are two basic situations:

1. The checkpoint data set is the only data set on a volume or resides on a volume that contains no data sets that are ever serialized by reserves. In this case, do not convert the reserve; include the name of the checkpoint data set in the SYSTEMS exclusion RNL.
2. The checkpoint data set resides on a volume that contains other data sets that are serialized by reserves. Such use of a volume contradicts suggestions for placement of the JES2 checkpoint data set. If your installation requires such use, then you must convert the reserves for all resources on the volume, including the checkpoint data set. In this case, include the names of all data sets in the RESERVE conversion RNL.