When planning for a multisystem environment, consider the following items:
The Global VCAT provides the mechanism by which the DASD buffer and the Virtual Volumes are shared between multiple CA Vtape Subsystems.
A CA Vtape Complex is created by sharing a Global VCAT between multiple Subsystems running on one or more systems.
More than one Complex can be created by creating and sharing different Global VCATs. This is typically only done to separate test and production data.
For performance reasons, CA Vtape utilizes hardware reserves against the DASD volume on which the Global VCAT resides to serialize updates.
The Global VCAT and Bootstrap data sets (BSDS) should never be allocated on the same DASD volumes as the dynamic cache data sets. The hardware reserve to update the Global VCAT will conflict with certain IDCAMS functions used to manipulate the dynamic cache data sets which could cause performance problems or a deadly embrace.
Virtual Devices are unique to an individual system and are not shared. For example, Virtual Device F05 on system A is not the same device as Virtual Device F05 on system B since they are being emulated by separate started tasks. Both devices can be online and in use at the same time on their respective systems.
Virtual Volumes can be shared across multiple subsystems just like physical tapes and are serialized just like physical tapes.
Concurrent read of a Virtual Volume is allowed if the reader is CA Disk. For instance, if multiple CA Disk auto-restores are triggered, on one or more systems, for data sets that reside on the same Virtual Volume, CA Vtape will allow the auto-restores to access that Virtual Volume at the same time.
Virtual Volumes may be Externalized by any active Externalization Server in a CA Vtape Complex and recalled by any active Recall Server in the Complex.
The RECYCLE utility can be run on any system to consolidate fragmented Backstore Tapes.
The CA Vtape parmlib supports symbolic substitution in its parmlib member names and parmlib attribute values. This support will allow you to use a single parmlib to support a multiple system configuration.
Note: For more information about symbolic substitution, see the chapter “Product Verification.”
