Determining the size of your checkpoint data set

Adequately determining the size of your checkpoint data set is critical to JES2's ability to initialize, and it should be large enough for future expansion. This section presents it as a 2-step procedure:

Step 1: Determine the number of 4K records needed to contain the checkpoint.
Step 2: Use the 4K value to determine the number of cylinders for DASD or kilobytes for a structure size.

If you don't want to calculate the size, you can use a trial-and-error approach by over-allocating the space (two or three times your current allocation) and let JES2 tell you with the $HASP296 or $HASP542 message if you need more. The largest checkpoint that JES2 will currently use is approximately 5,850 tracks on a 3390 device (Approximately 70,000 4K records). Allocating a new data set of this size will ensure that it can accommodate increasing any section to the maximum size.