The format of the DYNALLOC parameter is illustrated below.
DYNALLOC requests the dynamic allocation of SORTWK data sets on device type d. Specify the device type either as a decimal number (e.g., 3390) or by the system generic name (e.g., SYSDA). Any disk device accepted for a SORTWK DD statement can be specified. Note that if VIO is specified it will be ignored, and the installation default for the DYNALLOC device type will be used in its place.
Note that the DYNALLOC parameter may be used alone, without any subparameters. In this case, the DYNALLOC installation default settings are used.
For MAXSORT applications, n is the number of SORTWK data sets that will be allocated. As many as 32 SORTWK data sets can be specified. The default for n is 3.
For non-MAXSORT applications, n can be 1 through 255. This value specifies the number of SORTWK data sets that can potentially be allocated. For values of n that are 31 or less, MFX can automatically raise the number to 32 if the application requires it. When n is 33 through 255, this value specifies the maximum number of SORTWK data sets that can be allocated.
DYNALLOC=OFF can be specified to override a DYNALLOC=ON installation default.
Normally for both MAXSORT and non-MAXSORT applications, any SORTWK data sets provided in the JCL will contribute towards the value of n. For instance, if n was set to 40 in a non-MAXSORT application and 30 SORTWKs were provided in the JCL, DYNALLOC could obtain 10 additional SORTWKs if needed. Note that there is an installation option to disable DYNALLOC if SORTWKxx DD statements are present.
MFX uses the value specified in the RETRY parameter to request automatic DYNALLOC retry. This facility attempts to avoid a sortwork capacity exceeded condition when disk space is not immediately available to satisfy a DYNALLOC request. MFX will automatically retry a specified number of times and wait a prescribed interval between DYNALLOC requests.
The nn in the first position designates the number of times MFX will retry a failed DYNALLOC request. The minimum allowed is 0 and the maximum is 16. The mm in the second position designates the number of minutes MFX waits between each DYNALLOC request. The minimum allowed is 0 and the maximum is 15. A value of 0 can be used to request an immediate retry. RETRY=OFF or an nn of 0 can be specified to override a RETRY=ON installation default.
In an environment where DFSMS manages temporary work data sets, the SC subparameter specifies a storage class s for MFX to use when dynamically allocating SORTWORK data sets. The storage administrator at your installation defines the names of the storage classes you can specify. Note that an installation written automatic class selection (ACS) routine can override the storage class you specify. If SMS is not installed or active to manage temporary work data sets, the d device specification will be used in the SORTWORK dynalloc request.