free up disk space, which is the prime reason for export. (Space is only freed up, if a chunk of
data is no longer referenced by any cartridges.)
CAUTION: Do not export cartridges that the backup application uses on a frequent basis as part
of a rotation strategy because it will not be able to write to the empty slot.
Figure 17 Cartridge export
Why use the Export functionality?
The main reason for using Export is to create more space on the HP D2D Backup System. If space
is not an issue, Copy is the recommended method for creating offsite backups, because it is
controlled solely from the Web Management Interface and will not impact any tape rotation
strategy. Export involves use of the backup application. It is directly analogous to moving a cartridge
in a physical library to a mail slot (import/export element) so that the backup administrator can
take it offsite or put it into a firesafe. Only a single copy of the cartridge exists. It is on physical
tape and no longer on the cartridge in the HP D2D Backup System. The backup application is fully
aware that the cartridge location is now offsite, so cannot overwrite it without explicitly asking for
the cartridge to be moved back into the library.
The main advantage of Export is that it frees up disk space on the HP D2D Backup System if
deduplication is disabled on the library device. However, care must be taken to ensure that future
backups do not fail. For example, if a weekly backup tape is "exported", it will not be available
for append or overwrite the next time it is required. Depending on the backup application
configuration it may be possible to simply create a new blank cartridge in the library for use the
next time a weekly backup is required, however, in some configurations it will be necessary to
re-import the physical copy in order for the next backup to occur successfully.
When would Export be used?
Cartridge exports are likely to be used when the user wishes to free up space on the HP D2D
Backup System by exporting to physical tape a cartridge that is used infrequently. For example,
if a rotation scheme uses twelve monthly tapes, it is safe to export a monthly tape from two months
ago because it will not now be required (except for infrequent restores) for another ten months.
The same applies to yearly tapes which may never be required again as they are kept forever.
When would I restore from an exported cartridge?
Restoring from an "exported" cartridge has a higher likelihood than from a copied cartridge,
because the data no longer resides on the HP D2D Backup System. If a restore from an "exported"
cartridge is required, the backup application will ask for the cartridge to be re-imported into the
44 Tape Attach information for G1 products
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