DEVICE TYPE 1 field (UNIT subsystem parameter)
The UNIT subsystem parameter specifies the device type or unit name that is to be used for storing archive log data sets.
| Acceptable values: | device type or unit name |
|---|---|
| Default: | TAPE |
| Update: | option 43 on panel DSNTIPB |
| DSNZPxxx: | DSN6ARVP UNIT |
The value can be any alphanumeric string. If you choose to archive to disk, you can specify a generic device type with a limited volume range. Db2 requires all archive log data sets that are allocated on disk to be cataloged. If the device type specifies disk, set the CATALOG DATA field on panel DSNTIPA to YES.
If the unit name specifies disk, the archive log data sets can extend to a maximum of 15 volumes. If the unit name specifies a tape device, Db2 can extend to a maximum of 20 volumes. If you chose to use disk, make the values of the PRIQTY and SECQTY subsystem parameters large enough to contain all of the data that comes from the active log data sets without extending beyond 15 volumes.
When archiving to disk, Db2 uses the number of online storage volumes for the specified UNIT name to determine a count of candidate volumes, up to a maximum of 15 volumes. If the archives are to be managed by SMS, do not use a storage class with the Guaranteed Space attribute. SMS attempts to allocate a primary extent on every candidate volume. This can result in allocation failures or unused space because the primary extent on each unused volume is not released when the archive data set is closed.