The RSRVJIZ option is used to reserve memory above the 2-gigabyte bar for system or exit requirements during a JCL-initiated sort.
Information about the RESERVEZ execution time parameter can be found in the Syncsort MFX Programmers Guide.
The amount of memory to be reserved can be specified in a decimal number of G for a gigabyte Memory Object, where G=1073741824 bytes.
For example: RSRVTIZ=253G indicates reserving a 253 gigabyte Memory Object.
The range is 0-255. The default is 0.