IBM TotalStorage 3494 Tape Library, Operator'S Manual

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activity are predictable, you can use the Inhibit Reclaim Schedule to inhibit reclaim
operations for the heavy mount activity periods. You can add up to 14 entries to
the schedule.
When there are less than ten scratch stacked volumes available in the VTS or
TS7700 Virtualization Engine, the Inhibit Reclaim Schedule is ignored. For the
Inhibit Reclaim Schedule to be in effect with non-invasive reclamation activity by
the VTS or TS7700 Virtualization Engine, more than 50 scratch stacked volumes
must be available.
Five lists and a set of check boxes are used to set up an inhibit reclaim entry. The
lists contain the following options:
v Day of week
Sunday through Saturday or Every day. If you select the Every day option, the
Start Time and Duration you enter apply to every day of the week.
v Start Time - Hour and Minute
The start hour and minute for the inhibit. A 24-hour clock is used where 00 in
the hour field means midnight.
v Duration - Hours and Minutes
The number of hours and minutes that the inhibit reclaim should remain in
effect. You can specify up to 167 hours and 59 minutes (seven days minus one
minute). Specifying the maximum essentially always inhibits reclaim.
v
Check boxes to indicate the VTS or TS7700 Virtualization Engine to which to
apply the schedule.
Add an entry to the inhibit reclaim schedule by selecting a day of week, a start
time, and the duration. Then select the Add push button.
Delete an entry by highlighting it in the list box, then selecting the Delete push
button.
The Reclaim Threshold Percentage identifies when a stacked volume is to be made
available for reclamation. Each stacked volume has some amount of active data
and some amount of inactive (no longer needed) data. If the percentage of active
data is less than the percentage specified in this window, the stacked volume is
available to go through reclamation. During the reclamation process all of the
active data from the original stacked volume is moved to another stacked volume.
After all active data is moved from the original stacked volume, it is set to scratch.
This makes it available for reuse.
The Reclaim Threshold Percentage is set at 10% initially. IBM recommends that you
start with this value and raise it slowly by 5% increments, as necessary. As a
general rule, try not to exceed 30%–40%. It is better to add additional stacked
volumes than to increase the Reclaim Threshold Percentage. The higher this
number is, the longer it takes the VTS or TS7700 Virtualization Engine to reclaim a
stacked volume because more data must be copied from one stacked volume to
another stacked volume. The Active Data Distribution bar graph assists you in
setting this number. See “VTS Active Data Distribution” on page 179 for
information about displaying the window. The Reclaim Threshold Percentage can
be set for all pools or, if the VTS is Advanced Policy Management capable, for each
individual pool. To set the Reclaim Threshold Percentage, select a percentage from
the pulldown next to the VTS. If the VTS is Advanced Policy Management capable,
select the push button
″
VTS x - Assign Percentages
″
to bring up the VTS
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3494 Tape Library Operator Guide