Monitor Deduplication
Implementing nTier Deduplication
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Virtual index tape status
VITs replace virtual tapes after they have been deduplicated. Use the VTL Console
to review the status of these virtual tapes:
1. Expand the
Virtual Tape Libraries
object.
2. Expand the library and the
Tapes
object.
3. Select a tape and locate the
VIT
field on the
General
tab.
If the
VIT
field displays
Yes
, all data on this VIT has been deduplicated. The tape
contains only pointers to its data on SIR storage.
If the
VIT
field displays
Mixed
, this VIT contains pointers to its data on SIR
storage as well as data that has not been deduplicated yet. This status can occur
due to a specified delay prior to deduplication (refer to
’Changing the default
deduplication properties’
) or due to power factors that may affect the number of
deduplication jobs that can run simultaneously.
If the VIT field displays
No
, the tape is not a VIT; the data on the tape has not
been deduplicated.
4. Select the
Layout
tab to display information about the physical devices that were
used to create this VIT.
Reclaiming Disk Space
During the reduplication process, only single instances of unique data are passed to
the deduplication repository. The original virtual tape is replaced with a VIT pointing
to deduplication storage.
Over time, VITs can be erased, formatted, or overwritten by your backup application
(such as when a tape has expired). It is also possible that you may have manually
deleted a VIT. When a VIT is eliminated, the pointers to deduplication storage are
deleted but the actual deduplicated data is not.
To reclaim disk space, right-click the nTier VTL and select
SIR
-->
Reclaim Disk
Space
.
A message is displayed when the process begins and again to confirm that the
process is complete. Click
OK
to close the confirmation.
When the process is complete, you can look at the Repository Usage Area on the
SIR Statistics tab to see how much
Data Space Used
has decreased.
Note:
Putting a VIT in the scratch pool of a backup application does not mean
that the storage used by that VIT can be reclaimed. Storage can be reclaimed
only when a VIT is deleted from the console or erased/formatted/overwritten by
the backup application.
