Description: Beginning with z/OS V2R1, a new TUNE installation default allows you to specify whether DFSORT should allocate storage in increments with additional disk work space to minimize the risk of failure, or to allocate all storage at initialization so disk work space allocation can be reduced. The IBM-supplied default for the new TUNE installation option is TUNE=STOR which specifies allocation of available central storage as needed in increments sized to balance resource usage for concurrent sorts. If you want DFSORT to allocate available central storage using fixed sized increments, as in previous releases, you can set TUNE=OLD.
| Element or feature: | DFSORT. |
| When change was introduced: | z/OS V2R1. |
| Applies to migration from: | z/OS V1R13 and z/OS V1R12. |
| Timing: | Before the first IPL of z/OS V2R1. |
| Is the migration action required? | Yes, if the default value TUNE=STOR is not acceptable. |
| Target system hardware requirements: | None. |
| Target system software requirements: | None. |
| Other system (coexistence or fallback) requirements: | ICEPRMxx member(s) of PARMLIB can be shared between systems running different releases of DFSORT. Any installation options specified in the ICEPRMxx member that are only supported in the newer release of DFSORT will be ignored on the system using the earlier release of DFSORT. |
| Restrictions: | None. |
| System impacts: | None. |
| Related IBM® Health Checker for z/OS® check: | None. |