IBM TotalStorage 3494 Tape Library, Operator'S Manual

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Note: Media type JB is not supported with VTS.
Table 13. Free Storage Threshold (GB) for JA-, JB-, and JJ-Type Cartridges
Free Storage Threshold (GB) for JA-, JB-, and JJ-Type Cartridges
Scratch Stacked Volumes
VTS Model
Cartridge
Type
Data
Compression
Feature 10 30 50
3494 B10 and
B20 VTS or
TS7700
Virtualization
Engine
JA included 3,000 GB 9,000 GB 15,000 GB
3494 B10 and
B20 VTS
orTS7700
Virtualization
Engine
JB included 7,000 GB 21,000 GB 50,000 GB
3494 B10 and
B20 VTS
orTS7700
Virtualization
Engine
JJ included 600 GB 1,800 GB 3,000 GB
When only ten scratch stacked volumes are available, the VTS or TS7700
Virtualization Engine performance may be affected by reclamation, because the
Inhibit Reclaim Schedule is ignored. Reclamation is necessary to provide stacked
volumes for copying data from the tape volume cache. However, when more than
50 scratch stacked volumes are available, reclamation is non-invasive and occurs
only when allowed by the Inhibit Reclaim Schedule. A balance of performance,
excessive host messages, and additional cartridge expense may be achieved by
using a Free Storage Threshold (GB) representative of 30 stacked volumes.
The VTS/VE Management Policies window has the following push buttons:
Add Adds an entry to the Inhibit Reclaim Schedule.
Delete Deletes an entry from the Inhibit Reclaim Schedule.
Save Closes the VTS Management Policies window and saves all the changes
made to the Inhibit Reclaim Schedule, the Reclaim Threshold Percentage,
and the Free Storage Threshold (GB).
Cancel
Closes the VTS Management Policies window without saving any of the
changes.
Help Provides help about the VTS Management Policies window.
Manage Unassigned Volumes
Note: This window does not apply to the TS7700 Virtualization Engine.
The Manage Unassigned Volumes window (Figure 150 on page 250) opens
automatically under the following conditions:
v
When the 3494 Tape Library is in Import mode
Chapter 6. Advanced Operating Procedures
249