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HP StorageWorks 9000 - Virtual Library System - Deduplication Issues

HP StorageWorks 9000 - Virtual Library System
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2. Delete all pools associated with the library (see Deleting a Copy Pool).
NOTE:
Deleting the pools automatically moves all virtual cartridges from within the pool to the
firesafe.
3. Unmanage the physical library to be replaced (see Managing and Unmanaging a Destination
Library).
4. Replace the library or robotics card.
5. Manage the new physical library (see Managing and Unmanaging a Destination Library).
6. Manually recreate the storage pools associated with the new library using the information written
down at the beginning of this procedure.
The virtual tapes that were moved into the firesafe will automatically return to their previous
locations.
Deduplication Issues
SolutionPossible causesSymptom
Consider using cartridges that are
smaller than the sum of your daily
backup jobs so the cartridges dedu-
plicate sooner.
The VLS does not free up storage
on a cartridge until:
At least two full backups of the
same policy exist on different
cartridges
The delta-differencer has pro-
cessed all of the backup sets on
the cartridge
The cartridge is physically full
The VLS is not deduplicating the
backup jobs.
None
The compression ratio depends on
the amount of data changed
between the backup sets. In addi-
tion, not all data is deduplicated.
For example, files less than 32 KB
in size and backup sets less than 1
MB are ignored. If your data sets
do not change significantly
between backups, or if they contain
many small files, the compression
ratio may be low. This is expected
behavior and does not indicate a
problem.
The deduplication compression ra-
tio is low.
In time, the ratio will improve as
more backup sets are deduplicated.
After 50 versions of a backup set
have been deduplicated, the VLS
automatically restarts the deduplic-
ation process as though starting
from scratch. As a result, the com-
pression ratio will drop.
The deduplication compression ra-
tio was fine, but suddenly went
down significantly.
HP StorageWorks 293

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