Specifying which volumes to dump and the dump classes to use
DFSMShsm must be told what volumes to dump and what dump classes to use for the volumes to be dumped. This specification comes from the storage group or copy pool.
Storage group
The AUTO DUMP attribute specifies whether DFSMShsm is to perform automatic dumps on the volumes assigned to the storage group. In the example system, the AUTO DUMP attribute for all storage groups is AUTO DUMP = Y.
The DUMP CLASS attribute determines two controls for DFSMShsm: (1) the dump classes to which the volumes associated with the storage group are dumped and (2) how many dump copies are made when the dump occurs. The number of dump classes specified for any storage group determines the maximum number of copies that are made for any one dump. You can specify up to five dump classes for each storage group. Parameters in the dump class determine whether a dump copy is made for that particular dump class on that particular day.
The space management example (Figure 1) shows how host 1 can be limited to doing space management only for storage group 1. Dump for any of the storage groups is not being limited to a single host. However, should you want to limit the processing to a single host, you can use the DUMP SYSTEM/SYSPLEX NAME attributes in the same way as the MIGRATE SYSTEM/SYSPLEX NAME attribute. Figure 1 shows the dump management attributes that have been added to the storage groups in the example system.
For more information about storage groups and their function in SMS, see z/OS DFSMSdfp Storage Administration.
Copy pool
- Field
- Description and use
- Auto Dump
- The Auto Dump field specifies whether to do automatic dump processing for volumes in the copy pool. Type Y to enable automatic dump processing for the copy pool. If a generation 0 DASD version exists and the dump state of that version is either PARTIAL, FAILED, or NONE, automatic dump processes the version.
- Dump Class
- The Dump Class fields define the dump class name for fast replication dump to use. These fields are used by the DFSMShsm dump function to know how to manage both automatic dump and FRBACKUP dumps of the copy pool. Up to 5 dump classes can be specified for the copy pool; therefore, up to 5 copies can be created per dump version.
- Dump Sys/Sys Group Name
- The Dump Sys/Sys Group Name field specifies the system to which this copy pool has affinity.
- Number of DASD Fast Replication Backup Versions with Background Copy
- The Number of DASD Fast Replication Backup Versions with Background Copy field specifies the number of backup version (0 to 85, or blank). Up to 85 DASD versions can be specified with a default of 2. If 0 is specified, it implies a NOCOPY environment. In a NOCOPY environment, unless the copy pool is defined with fast reverse restore capability, you cannot recover the backup version from DASD – the only purpose of the backup version is to be available as a source for dump processing.
For more information about the copy pool construct, see Using the copy pool construct for fast replication setup.