HP D2D100, Руководство пользователя

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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 inde fi nitely. 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 library device on the HP D2D is overwritten (accidentally) by the
backup application. The backup application database is updated to re fl ect 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 library 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
library on the existing D2D and then import any copied cartridges back into the new device for
use with restores at a later date. If a restore is urgently required, the administrator can put the
copied cartridge into a physical tape drive attached to the host and restore directly from that. In
either case, the backup application is aware of the cartridge’s existence.
• Both the D2D system and the host are lost. In this case, the physical cartridge copy (as long as it
was a full system backup) can be used for disaster recovery onto new or repaired server hardware
using a tape device attached to the host server.
Disadvantages of Copy
1. Data is left on the HP D2D Backup System; no disk space is freed by copying to physical
cartridge.
2. It is possible for the backup application to overwrite the cartridge on the HP D2D Backup System
and thus become unaware of the data that has been copied to the physical cartridge.
Cartridge export
The backup application on the host is used to back up data to a slot on the library device (or to a
standalone tape drive device) in the HP D2D Backup System. It is also used to move the data from the slot
into the mail slot. This creates an empty slot where the data was moved.
The Web Management interface on the HP D2D is used to
Export cartridge data from the mail slot on
the HP D2D Backup System to the attached tape storage device. After a successful export, the data
is removed from the HP D2D Backup System and the mail slot becomes empty. (If the export fails,
the data remains in the mail slot.) Export removes the data and frees up disk space on the HP D2D
Backup System and is useful for long term archival (for example in a yearly tape in a rotation scheme). If
restore is needed, data can be imported (or moved back) into the HP D2D Backup System. Export is not
recommended with deduplicating libraries as it does very little to 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.)
D2D Backup System HP D2D2503
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