Because SDSP data sets reside on ML1 volumes, they can be involved in various ways with DFSMShsm processing of level 0 volumes and ML2 volumes. For example, an SDSP data set can be a target for automatic primary space management and, at the same time, the SDSP can be a source for a user’s recall of a small data set from an SDSP data set. SDSP data sets can be included in aggregate backup and SDSP data sets require cleanup after a user recalls a migrated data set. Additionally, the AUDIT and FREEVOL functions can be run against volumes on which SDSP data sets reside.
Because SDSP data sets are potentially involved in various DFSMShsm processes, there are times when concurrent DFSMShsm processing activities cause contention for SDSP data sets. Figure 1 shows that an SDSP data set can be effected by various DFSMShsm processes. Table 1 shows the usage priorities for SDSP data sets and describes how DFSMShsm resolves contention for SDSP data sets.
| Function That Has SDSP | Function That Needs SDSP | Result |
|---|---|---|
| Migration (L1 to L2)
Recall FREEVOL (source) AUDIT MEDIACONTROLS (source) Aggregate backup |
Migration (L0 to L1) | If all other SDSP data sets are presently in use, this small user data set is skipped and, most likely, can migrate to an SDSP during your next migration window. |
| Migration cleanup or migration (L1 to L2) | Migration (L0 to L1) | Migration cleanup and level 1 to level 2 migration are functions
of automatic secondary space management. Because SDSP data sets can
be open for a long time during migration cleanup or during level 1
to level 2 migration, it is likely that they will be in use. If all
SDSP data sets are presently in use, this small user data set is skipped
and, most likely, can migrate during your next migration window.
Note: Do not run automatic primary space management and automatic
secondary space management concurrently.
|
| Migration (L0 to L1) | Recall | Migration processing gives up its use of this SDSP data set to the recall function that requests the SDSP data set. If all SDSP data sets are presently in use, the migration of this small user data set is skipped and, most likely, can migrate during your next migration window. |
| Recall | Recall | The first recall request to access the SDSP data set completes its processing. Other recall requests retry the SDSP data set request and, most likely, will be successful. |
| FREEVOL (source)
AUDIT MEDIACONTROLS |
Recall | Because FREEVOL and AUDIT MEDIACONTROLS are relatively long-running processes, the recall request will either retry until successful or retry until timing out and failing. |
| Migration cleanup | Recall | Migration cleanup gives up its use of this SDSP data set to the recall function that requests the SDSP data set. Migration cleanup skips its processing of the SDSP data set. |
| Aggregate backup | Recall | Recall processing retries the recall request and, most likely, will be successful after the aggregate backup has finished. |
| Migration (L0 to L1)
Recall AUDIT MEDIACONTROLS Migration cleanup Aggregate backup |
FREEVOL (source) | FREEVOL processing fails. |
| Migration (L0 to L1)
Recall AUDIT MEDIACONTROLS Migration cleanup Aggregate backup |
FREEVOL (target) | If the target SDSP data set cannot be made available to FREEVOL processing, this small data set is skipped and cannot be moved from the source SDSP data set. |
| Migration (L0 to L1)
Recall FREEVOL AUDIT MEDIACONTROLS Migration cleanup Aggregate backup |
AUDIT MEDIACONTROLS | If this SDSP data set is in use by other functions, the AUDIT request for the SDSP data set fails. |
| Migration (L0 to L1)
Recall FREEVOL AUDIT MEDIACONTROLS Aggregate backup |
Migration cleanup | If the SDSP that is needed by migration cleanup is in use, this small user data set is skipped and it is deleted the next time automatic secondary space management is run. |
| Migration (L0 to L1) | Aggregate backup | Migration processing gives up its use of the SDSP data set. If all SDSP data sets are presently in use, this small user data set is skipped and, most likely, can migrate during your next migration window. |
| Recall | Aggregate backup | Aggregate backup will retry its request for the SDSP and will eventually be granted access. |
| FREEVOL (source) | Aggregate backup | Aggregate backup fails. |
| FREEVOL (target) | Aggregate backup | FREEVOL processing gives up its use of this SDSP data set to the aggregate backup request. If no other SDSP data sets are available, FREEVOL processing skips the data sets. |
| AUDIT MEDIACONTROLS | Aggregate backup | Aggregate backup fails. |
| Migration cleanup | Aggregate backup | The SDSP data sets are released from migration cleanup. Migration cleanup skips processing from this SDSP data set. |
| Aggregate backup | Aggregate backup | The first aggregate backup request to reach the SDSP gets access to the SDSP. Other aggregate backup requests will retry until successful. |
The functions of aggregate backup, aggregate recover, FREEVOL, and AUDIT should be run at times when they will not be contending for the use of the same SDSPs.