A VVDS is defined with the name SYS1.VVDS.Vvolser, where volser is the volume serial number of the volume containing the VVDS. SYS1.VVDS.Vvolser does not have to be cataloged in the master catalog.

An explicitly defined VVDS is not related to any BCS until a data set or catalog object is defined on the volume. As data sets are allocated on the VVDS volume, each BCS with catalog or SMS-managed data sets residing on that volume is related to the VVDS.

An explicit definition of a VVDS does not update any BCS and, therefore, can be performed before the first BCS in the installation is defined.

Explicitly defining a VVDS is usually appropriate when you are initializing a new volume. If you are not running SMS, and a volume already contains some non-VSAM data sets, it is appropriate to allow the VVDS to be defined implicitly. The default space allocation will be the values that the operator specified on the most recent F CATALOG,VVDSSPACE command. If that command has not been issued since IPL, the default space allocation will be TRACKS(10 10).

If you are explicitly defining a VVDS, see Estimating Space Requirements for the VVDS for an explanation of how to estimate the size of the VVDS.