For each HSMS job, the HSMS administrator can specify the priority with which it is to be processed. For example, important jobs such as system backups can be assigned a high priority and be started even if there are a large number of jobs from nonprivileged users in the system.
To do this, the HSMS administrator can use the REQUEST-PRIORITIES operand in the HSMS statement MODIFY-HSMS-PARAMETERS to define a range of default priorities in the HSMS control parameters. A default priority can be assigned to each archive type:
Backup archive: default priority for reading and writing
Long-term archive: default priority for reading and writing
Migration archive: default priority for reading and writing
Archive for node backups: default priority for reading and writing
Archive for the long-term archival of nodes: default priority for reading and writing
Shadow archive: default priority for reading and writing
Default priority for import and export
Default priority for implicit recall
The assigned default priorities can be viewed using the HSMS statement SHOW-HSMS-PARAMETERS (in the REQUEST-PRIORITIES information block).
The HSMS administrator can then define the read and write priorities for each individual archive. It can either define a specific priority or use the default priority for the specified archive type. This is done by using the REQUEST-PRIORITIES operand in the HSMS statements CREATE-ARCHIVE and MODIFY-ARCHIVE-ATTRIBUTES.
By default, archives belonging to nonprivileged users contain a reference to the default priorities.
Priorities for shadow archives are taken into account only for HSMS statements which are exclusively executed in the shadow archive – for example a RESTORE-FILES statement for a shadow archive.
When a request for an archive is issued, the processing priority is determined on the basis of the individual read and write priorities for this archive. If the default priority has been defined for the archive in question (REQUEST-PRIORITIES=*STD) then the default priority for this archive type is used. A distinction is made between read and write requests.
Exceptions
There are the following two exceptions to this general procedure:
The serial processing of requests is taken into account (see section "Request-time control"). This may modify the priority of a request.
In the case of serial processing, the requests are worked through as “request sets”. In consequence, each request has the priority of the set. New requests have the same priority as the preceding requests in the set.Requests which the HSMS administrator issues as express requests are always processed with the highest priority. However, if express requests are processed serially, the priority may be reduced as described above.