RECYCLEINPUTDEALLOCFREQUENCY: Allowing periodic deallocation of input unit during recycle processing
Explanation: RECYCLEINPUTDEALLOCFREQUENCY(BACKUP(bfreq) MIGRATION(mfreq)) is an optional parameter that you use to periodically deallocate an input unit during recycle processing. This dynamically changeable parameter prevents DFSMShsm from possibly keeping an input unit allocated for hours.
Tape Library Relationship: In a tape environment
where contention for tape drives may be a consideration, the following
table shows BACKUP(bfreq) or MIGRATION(mfreq) values
that are recommended when you recycle single-file-format cartridges:
Type of Environment |
Value |
Resulting Allocation |
|---|---|---|
| A single IBM® 3494/3495 Tape Library Dataserver environment having all compatible drives | 0 | The input unit is allocated for the duration of recycle processing. |
| An SMS-managed tape environment that has multiple IBM 3494/3495 machines where inputs can come from different ATLs | 0 | A unique allocation is allowed for each input connected set. |
| A BTLS-managed environment that has multiple IBM 3494/3495 machines where inputs can come from different ATLs | 1 | RECYCLE allocates tape drives for each connected set in the correct library. |
| A multiple non-SMS-managed tape library where not all backup or migration tapes are in a single library (for example, an STK® ACS cluster where you want to prevent pass-through processing) | 1 | RECYCLE allocates tape drives for each connected set in the correct library. |
| An environment that has incompatible tapes even though they may appear the same, including when one has a mix of real and emulated devices, such as 3490s and emulators of 3490s | 1 | RECYCLE allocates tape drives for each connected set. |
| A tape environment with manual tape operators, but no incompatible mix of real and emulated devices that appear as the same device | 5 or 10 | New allocations are allowed every 5 to 10 input connected sets. |
| Subparameter | Explanation |
|---|---|
| BACKUP(bfreq) | During recycle processing of backup volumes, deallocation of an input unit will occur after the specified number of input connected sets representing single-file-format cartridges have been processed. For bfreq, substitute a decimal number from 1 to 255 for the number of connected sets to process before deallocation of the input unit. Specifying 0 will retain the input unit until recycle processing has completed. |
| MIGRATION(mfreq) | During recycle processing of migration volumes, deallocation of an input unit will occur after the specified number of input connected sets representing single-file-format cartridges have been processed. For mfreq, substitute a decimal number from 1 to 255 for the number of connected sets to process before deallocation of the input unit. Specifying 0 will retain the input unit until recycle processing has completed. |
Note:
- For example, specifying SETSYS RECYCLEINPUTDEALLOCFREQUENCY(BACKUP(20)) will deallocate the input unit every 20 input backup connected sets. Using SETSYS RECYCLEINPUTDEALLOCFREQUENCY(MIGRATION(1)) will deallocate the input unit after each input migration connected set has been processed.
- The input unit will always be deallocated between connected sets when the tape volume is not a single-file-format cartridge.
SMS relationship: Parameter has the same meaning when applied to SMS-managed or non-SMS-managed DASD volumes or data sets.
SETSYS default: None.
DFSMShsm default: If you do not specify this parameter (or either subparameter) on any SETSYS command, the DFSMShsm default is that recycle processing will keep the input unit allocated until the processing of that type of volume (backup or migration) is complete.