Using the common storage tracking function

Common storage tracking collects data about requests to obtain or free storage in CSA, ECSA, SQA, and ESQA. You can use this data to identify jobs or address spaces that use up an excessive amount of common storage or have ended without freeing common storage. If those jobs or address spaces have code to free that storage when they are canceled, you might relieve the shortage and avoid an IPL if you cancel those jobs or address spaces using an operator command.

You can use Resource Measurement Facility™ (RMF™) or a compatible monitor program to display the data that the storage tracking function collects. You can also format storage tracking data in a dump using interactive problem control system (IPCS). For information on how to use IPCS to format common storage tracking data, see the description of the VERBEXIT VSMDATA subcommand in z/OS MVS IPCS Commands.

The OWNER parameter on the CPOOL BUILD, GETMAIN, and STORAGE OBTAIN macros assigns ownership of the obtained CSA, ECSA, SQA, or ESQA storage to a particular address space or the system. To get the most value from the common storage tracking function, ensure that authorized programs specify the OWNER parameter on all CPOOL BUILD, GETMAIN, and STORAGE OBTAIN macros that:

Request storage in CSA, ECSA, SQA, or ESQA, and
Have an owning address space that is not the home address space.

IBM® recommends that common storage tracking always be activated.

You can turn storage tracking on by activating a DIAGxx parmlib member, either at IPL (specify DIAG=xx as a system parameter) or during normal processing (enter a SET DIAG=xx command). For more information about using SET DIAG=xx, see z/OS MVS System Commands.

If you do not specify a DIAGxx parmlib member at IPL, the system processes the default member DIAG00. If DIAG00 does not exist, common storage tracking will not be turned on. Common storage remains active until turned off through a SET DIAG=xx command. DIAG00 also turns off the GFS trace function, which is described in Using GETMAIN/FREEMAIN/STORAGE (GFS) trace.

IBM also provides the DIAG01 parmlib member, which turns the common storage tracking function on, and DIAG02, which turns the common storage tracking function off. Your installation must create any additional DIAGxx parmlib members.