The DYNALOC option is used to dynamically allocate SORTWK data sets. These data sets are deallocated at the conclusion of all program-invoked sorts, and MFX may override specified values when it finds that sorting can be completed more efficiently. Some sort applications that use SUM, DUPKEYS, OUTREC, OUTFIL, or VSAM SORTOUT and do not provide JCL SORTWORKs may automatically have DYNALOC enabled. Therefore, you should ensure that appropriate options are set at installation so that DYNALOC can be used effectively.
If SMS is not installed or active for temporary DASD work data sets, use cccccccc in the first subparameter to give the generic name of the class from which the sort should dynamically allocate the SORTWK data sets. (Note that VIO is not accepted as a unit device.) SYSDA is the default. If SMS is active, refer to the SC sub-parameter of DYNALOC described below, at the end of this section.
Use nn in the second sub-parameter to specify the number of SORTWK files to be dynamically allocated for a MAXSORT. The maximum number allowed is 32, and the default is 3. Note that the MAXNUM sub-parameter of DYNALOC (see definition below) is not applicable to a MAXSORT application.
ON in the third sub-parameter tells MFX to dynamically allocate SORTWK files when appropriate. Dynamic allocation can be provided even if it is not specified as a PARM or on the SORT control statement. ON is the default. OFF tells MFX that no dynamic allocation should be done for a sort.
ON in the fourth sub-parameter tells MFX that, although SORTWK files have been allocated in the JCL, additional SORTWK files should be dynamically allocated. ON is the default. OFF in the fourth subparameter tells MFX not to dynamically allocate additional SORTWK files if SORTWK files have been allocated in the JCL. Note that this specification will only be used with MAXSORT.
Use the nnnnnnnnnn in the fifth sub-parameter to specify the total amount of primary space to be obtained by dynamic allocation of SORTWK files for MAXSORT applications. The default value for primary space is 6 million bytes. The maximum value is 4,294,967,295.
Use the nnnnnnnnnn in the sixth sub-parameter to specify the amount of secondary space to be obtained by dynamic allocation of SORTWK files for MAXSORT applications. The default value for secondary space is 3 million bytes. The maximum value is 4,294,967,295.
In the seventh sub-parameter, specify the DASD with the smallest track capacity that might be encountered at your installation by a dynamically allocated SORTWK data set. The default is 3390. If, during dynamic allocation, MFX receives a device with a track capacity smaller than the one specified, it may ignore the specified device type. Below is a table of the devices and their track capacities:
|
TYPE |
TRACK CAPACITY |
|---|---|
|
3380 |
47476 |
|
3390 |
56664 |
|
9345 |
46456 |
Specify RETRY to enable MFX to perform automatic DYNALLOC retry. This facility will attempt to avoid a SORTWK capacity-exceeded condition when disk space is not immediately available to satisfy a DYNALLOC request. MFX will automatically wait a prescribed length of time between retries and will retry a request a specified number of times.
Use the mm in the first position in the RETRY sub-parameter to specify the number of times MFX is to retry a failed DYNALLOC request. The minimum value allowed is 0 and the maximum value is 16. The default of 5 tells MFX that automatic DYNALLOC RETRY is to be retried 5 times.
Use the nn in the second position in the RETRY sub-parameter to specify the number of minutes to wait between each DYNALLOC request. The minimum value allowed is 0 and the maximum value is 15. The default of 3 tells MFX to wait 3 minutes between each RETRY attempt.
If SMS is active to manage temporary work data sets, the SC sub-parameter can be specified to instruct MFX to DYNALLOC SORTWKs from storage class (STORCLAS) ssssssss. If this parameter is not specified in an SMS environment, MFX will dynamically allocate devices from the generic class cccccccc specified in the first sub-parameter. Note that an installation written automatic class selection (ACS) routine can override the DYNALOC parameter you specify.
The MAXNUM sub-parameter is used to set the maximum number of SORTWK files that could be used in non-MAXSORT applications. If the number of SORTWK data sets specified in the JCL is less than MAXNUM, MFX may dynamically allocate more data sets to bring the total number of SORTWK data sets up to MAXNUM. Specify a value from 32 to 255. MFX will automatically determine the appropriate number of SORTWK files to use within the cap specified. Note that the specification of values greater than 32 will increase the need for virtual storage below the 16-megabyte line. This storage is required for system control blocks such as DCBs. Since most applications can be supported with the minimum of 32, it may be best to specify at run time, via the DYNALLOC parameter, a larger value when it is required.
The DSNTYPE sub-parameter is used to control the DSNTYPE attribute when MFX performs DYNALLOC. The allowed values are LARGE and BASIC. DSNTYPE=LARGE is the default. When DSNTYPE=BASIC is specified, MFX will not use the DSNTYPE=LARGE attribute when performing DYNALLOC, and the upper limits for primary and secondary allocations are lowered accordingly. (For the effects of the DSNTYPE attribute, refer to the section titled DSNTYPE Parameter in the DD Statement chapter in the IBM z/OS MVS JCL Reference.)
The EATTR sub-parameter is used to control the EATTR attribute when MFX performs DYNALLOC. The allowed values are OPT and NO. EATTR=OPT is the default. (For the effects of the EATTR attribute, refer to the section titled EATTR Parameter in the DD Statement chapter in the IBM z/OS MVS JCL Reference.)
As noted above, if you want to enable DYNALOC with the default settings, specify DYNALOC=(,,ON). This is the minimum specification to ensure dynamic allocation for SORTWK data sets.