DFSMShsm allows up to 30 secondary space management tasks to run
concurrently within a single DFSMShsm host during automatic secondary
space management. Use the MAXSSMTASKS parameter of the SETSYS command
to control the maximum number of automatic secondary space management
tasks that you want to run concurrently. Up to 15 tasks are available
for cleanup functions and up to 15 tasks are available for tape movement
functions. Secondary space management cleanup consists of the following
functions:
- Expiration of migrated data sets
- Deletion of MCDS records that are no longer needed
- Deletion of SDSP records that are no longer needed.
Tape movement functions consists of moving ML1 data to ML2 tape,
also referred to as ML1-to-ML2 data movement.
This SETSYS MAXSSMTASKS parameter is dynamic. If you change the
number of tape movement tasks or cleanup tasks while secondary space
management is active, the new number of tasks are immediately effective.
If you do not specify this parameter on any SETSYS command, the
default value for the maximum number of concurrent cleanup tasks is
2 and the default value for the maximum number of concurrent tape
movement tasks is 1. To aid in the processing of the deletions initiated
by secondary space management, the default for the number of recall
tasks is 15. You can use the SETSYS MAXRECALLTASKS command to change
this default.
Example: You can add the following command
to the ARCCMD
xx member in each DFSMShsm hosts
to handle automatic secondary space management:
SETSYS MAXSSMTASKS(CLEANUP(2) TAPEMOVEMENT(1))
Note: Each task that you specify for tape movement requires
a tape unit. If you are using the duplex tape option, two tape units
per task are required.