BRMS uses virtual devices differently than physical storage devices.
Virtual Tape Library (VTL) drives offer dynamic volume sizing which may not allocate the full tape volume size that was requested. If your BRMS backup plan uses VTLs, large size tape volumes will improve BRMS operational efficiency.
To optimize the VTL with BRMS, review the report output (QP1ABS) from PRTRPTBRM TYPE(*CTLGRPSTAT)
The Start Media Balancing for BRM (STRBALBRM) command balances expired media ownership to match the required number of media needed for systems within a BRMS network.
In versions 7.2 and later with the following PTFs: 7.3 SI68856 | 7.2 SI68855
BRMS will sort the available device resources names alphabetically and pick the first available virtual device resource.
BRMS may pick a device which currently has a different image catalog loaded.
If you have virtual devices which you are using for native operations and don’t want BRMS to use it, the device needs to be allocated.
To allocate a virtual device use the following command:
ALCOBJ ((‘virtual-device-description-name’ *DEVD *EXCLRD))
BRMS will allocate the device and load the appropriate image catalog on the device for the duration of the backup or restore operation. After the operation is complete BRMS will unload the image catalog and deallocate the device.
In versions 7.2 and later with the following PTFs: 7.3 SI68856 | 7.2 SI68855
BRMS will generate its own virtual device using the naming convention Q1AVTAPnnn for virtual tape or Q1AVOPTnnn for virtual optical.
NOTE: The operating system only allows 35 virtual device resource names to be created. If there are not enough resources available for BRMS to use for the device descriptions being generated, the vary on of the generated device description will fail. Operators will need to free up unused virtual resource names for BRMS to use for the operation to complete.
Operators should avoid using these BRMS named devices.
BRMS will vary on and allocate the device and load the appropriate image catalog on the device for the duration of the backup or restore operation. After the operation is complete BRMS will unload the image catalog and deallocate the device.