Besides its own system data sets, CICS® also
uses some MVS™ data sets.
About this task
These data sets are:
| Data set |
Owned or used by |
Other comments |
| SDUMP data sets |
MVS SDUMP macro |
Used by CICS for system dumps through the MVS
SDUMP macro. |
| SMF data sets |
System management facility |
Used by CICS monitoring and statistics domains
for monitoring and statistics records. |
| GTF data sets |
Generalized trace facility |
Used by CICS trace domain for CICS trace entries. |
Procedure
-
Recalculate the size of these system data sets, taking into account the increased volumes of data that CICS generates.
For example, for an SDUMP data set you must have at least 25 cylinders of a 3380 device, or the equivalent. For guidance information about calculating the size of SDUMP data sets, see the
z/OS MVS Initialization and Tuning Guide.
- To prevent the SDUMP data sets from becoming full of unwanted
SDUMPs, suppress the SDUMPs as described in Suppressing system dumps that precede ASRx abends.
SDUMPs
can precede ASRA, ASRB, and ASRD abends after the message DFHAP0001.
- If you are collecting CICS interval statistics frequently,
or the volume of statistics at each interval is high, then you must
take this into account when sizing your SMF data sets.
CICS
can write records to SMF of up to 32 756 bytes, resulting in SMF writing
spanned records to the SMF data sets. For more efficient use of DASD,
you should consider creating the SMF data sets to be used by CICS
with a control interval size of either 16 384 bytes (16 KB) or 8192
bytes (8 KB). If you use other control interval sizes you must consider
the trade-off between efficient use of DASD, SMF data set I/O performance,
and the possibility of data being lost due to insufficient SMF buffers.
-
If you are collecting CICS monitoring data, you must size the amount of data that is written when the monitoring classes are active.
-
If you are running CICS with GTF trace on, make allowance for CICS trace entries in the GTF data sets.