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Larger logical volume size support in the Virtual Tape Server z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Object Support SC23-6866-00 |
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By default, the IBM 3494 Virtual Tape Server and the IBM TS7700
Virtualization Engine supports two logical volume sizes 400 MB and
800 MB, which correspond to the supported 3490 media types: cartridge
system tape (MEDIA1) and enhanced capacity cartridge system tape (MEDIA2).
Using outboard policy management support, the default volume size
can be overridden at the library through a data class policy specification.
If a maximum volume size is specified in the assigned data class,
that volume size will override the default volume size for the volume
when it is first mounted. A logical volume's maximum volume size can
then change when it is mounted as a scratch volume again. However,
for a TS7700 Virtualization Engine at Release 1.6 or higher, the logical
volume's maximum size can change when the volume is written from load
point, for either a scratch or private (specific) request. Prior to
Release 1.6, the TS7700 retained the capacity of the logical volume
(on reuse), unless the volume was mounted as a scratch volume. Application
configuration-related changes may also be needed to fully utilize
the new logical volume sizes. In the case with OAM's Object Tape Support,
the TAPECAPACITY parameter in the SETOAM statement of the CBROAMxx
PARMLIB member is used to specify the larger logical volumes sizes.
For a 1000 MB logical volume, the capacity specified should be 1,000,000
KBs (1000 X 1000). Then for a 2000 MB logical volume, the capacity
specified should be 2,000,000 KBs (2000 x 1000) and for a 4000 MB
logical volume, the capacity specified should be 4,000,000 KBs (4000
x 1000). Refer to SETOAM statements for object tape storage for a description
of the TAPECAPACITY keyword associated with the SETOAM statement.
With OA24966, and starting with Release 1.4 of the TS7700 Virtualization
Engine (and only with the TS7700 Virtualization Engine), support was
added in OAM to obtain the size of the logical volume from the library.
With this added support, specification of the TAPECAPACITY keyword
may no longer be needed to utilize the capacity of the larger logical
volumes, if the needed software support is installed and the IBM virtual
tape libraries being used for OAM's object support are all TS7700
Virtualization Engines at Release 1.4 or above. For additional information
on outboard policy management refer to z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries.
Note: For virtual tape libraries that are not at Release
1.6 (or higher) of the TS7700 Virtualization Engine, the virtual tape
library will retain the capacity of the logical volume (on reuse),
unless the volume is mounted as a scratch volume. When using the larger
logical volume size support in the 3494 VTS or in prior release levels
of the TS7700, the recommendation is to use TAPERECYCLEMODE(MVSSCRATCH)
when recycling an object tape volume.
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Copyright IBM Corporation 1990, 2014
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