Compression; Cartridge Import - HP D2D Manual

HP D2D before it can be used for restore. Exported cartridges may also be used for disaster
recovery, as with copied cartridges.
Disadvantages of Export
1. Restores may take longer if a physical cartridge is required for the restore.
2. Backup applications may require the exported cartridge for the next job in their rotation
scheme.

Compression

When you are moving data from the HP D2D to physical tape, it is important to be aware that the
cartridge maximum size is the native size (without compression). HP StorageWorks tape drives
apply hardware compression, therefore, the data from the HP D2D Backup System is likely to
require less space on a physical tape cartridge. When moving data to a physical cartridge for
off-site storage, there is no need for concern if the data seems to utilize less space.
The capacity quoted for physical media assumes that the tape drive will be able to compress your
data and reduce the file sizes by 50%, but this can be achieved only if your data is not already
compressed. For example, JPEG pictures, movies, music or ZIP files, are already in compressed
formats: spreadsheets, text files, high-resolution graphics are not. Most users have a mixture of
compressed and uncompressed data and seldom achieve 50% compression.
Some users may choose to enable software compression from their backup application to increase
the storage space available to the backup application, but this can make backup jobs slower to
run. However, once software compression has been applied, the data is not further compressed
when it is exported to a physical tape directly attached to the HP D2D Backup System. This ensures
that the user knows exactly how much physical cartridge space is required for export or copy.

Cartridge import

The Web interface on the HP D2D is used to Import cartridge data from the attached tape storage
device to the mail slot on the HP D2D Backup System. The backup application on the host is used
to move the data from the mail slot back into one of the library slots.
Figure 18 Cartridge import
When you import a cartridge:
If it is less than 200 GB, the cartridge Max Size is set to 200 GB.
If it is over 200 GB, the cartridge Max Size is set to 400 GB.
Archiving methods 45