HP D2D100 Backup System - Manual (Page 85)

Step 2
Use HP D2D Web
Management Interface to
copy to tape drive.
Physical
Tape Drive
Cartridge
Step 1
Use backup application on
host to write to cartridge.
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HP StorageWorks D2D Backup System
Autoloader
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HP StorageWorks D2D Backup System
Autoloader
Figure 36 Cartridge copy
Why use the Copy functionality?
Copy creates two instances of the same cartridge; one stored on the HP D2D, the other on physical tape.
Logically these are the same cartridge and the backup application has no awareness that there are two
copies. If data from this cartridge is required for restore, the backup application will always restore the
data from the HP D2D if it is available. The physical cartridge is, therefore, an additional copy that will
be required only if the HP D2D is not available.
When would Copy be used?
Cartridge copies are likely to be appropriate when the user wishes to use the HP D2D Backup System for
all foreseeable restore processes but requires an additional offsite copy for insurance or data security
purposes. This may mean that weekly, monthly and yearly cartridges are copied. Weekly and monthly
physical cartridges may be rotated; the cartridges on the HP D2D Backup System are overwritten after a
period of time. Yearly cartridges may be kept indefinitely. Clear labeling of the cartridges in this case is
essential because the backup application may overwrite the cartridge on the HP D2D Backup System
and, therefore, lose any knowledge of the existence of the physical tape cartridge.
When is it necessary to restore from a copied cartridge?
There are three situations where it may be necessary to restore from the copied cartridge:
• The cartridge stored in the autoloader device on the HP D2D is overwritten (accidentally) by the
backup application. The backup application database is updated to reflect the new contents of
the cartridge and all knowledge of the old data is lost. If the backup administrator becomes
aware that this has happened, it is possible to import the physical cartridge back into the HP D2D
system, from where its data can be "imported" back into the application database for restore, if
required. In this case, because the backup application has overwritten the database entry for the
cartridge, some external knowledge of what is on the copied cartridge is required in order to be
able to decide whether the data on the copied cartridge is useful.
• The whole HP D2D Backup System or a complete autoloader on the HP D2D is accidentally
removed from the Web Management interface. The physical copy of the cartridge is the only
copy now in existence. The backup application is still aware of the cartridge’s existence because
it was not aware of the loss of the D2D system. The backup administrator has two options; if there
is no required restore at this point, the administrator can deploy a new HP D2D system or create
a new autoloader on the existing D2D and then import any copied cartridges back into the new
D2D Backup System 85