All JES2 buffers are maintained in a dynamic pool until required by an active function. The BUFDEF initialization statement defines the number of local I/O buffers to be acquired by JES2 (10 to 2000). To help you tune your system, you may wish to closely monitor local buffer usage during JES2 processing by issuing the $T BUFDEF command. (For performance considerations associated with buffer usage, see z/OS JES2 Initialization and Tuning Reference, SA32-0992.)

Use the $T BUFDEF command to specify the percentage of local buffers used at which JES2 alerts you of a local buffer shortage. The $HASP840 message displays the number of local buffers in use, the number currently free, and the percentage of usage at which you are alerted.

Use the $T SMFDEF command to monitor SMF buffers in the same manner. The $HASP841 message displays the current values of all the parameters on the SMFDEF initialization statement when you enter the $T SMFDEF command. The $HASP050 message alerts you of a shortage of either SMF buffers or local buffers. JES2 deletes this message when the resource shortage is relieved (by a decrease in resource use or an increase in the threshold).