Controlling the problem determination aid (PDA) facility

The problem determination aid (PDA) facility is automatically enabled during DFSMShsm startup. You can enable or disable PDA processing by the way you specify the SETSYS PDA(NONE|ON|OFF) command.

If you specify . . .	Then . . .
SETSYS PDA(NONE) during DFSMShsm startup	No dynamic storage is obtained, the DASD trace data sets are not opened, and no data is gathered.
SETSYS PDA(ON)	DFSMShsm requests storage for data accumulation and opens the DASD trace data sets if they have been allocated. If no DASD trace data sets have been allocated, the data is accumulated only in internal storage.
SETSYS PDA(OFF)	All data accumulation is halted, but the DASD trace data set remains open.

You should continuously enable PDA tracing when DFSMShsm is active; any resulting performance degradation is minimal.

The PDA log data sets are automatically swapped at DFSMShsm startup. There is no way to control swapping at startup, but there can be later times when you may want to switch the data sets before ARCPDOX is filled. To switch the data sets, use the SWAPLOG PDA command.

The z/OS DFSMShsm Diagnosis contains additional information about the PDA facility, or see Problem determination aid log data set size work sheet—Short-term trace history.

Note: If the DFSMShsm PDOX data set is on a non-SMS-managed volume that will be backed up, use the ALTERDS datasetname VERSIONS(0) command to prevent DFSMShsm from backing it up.

If the PDOX data set is on an SMS-managed volume that will be backed up, assign it to an SMS management class that does not allow backup copies.