HP D2D, User Manual, Page: 172 / 210

Archive from host to tape process
This process is controlled by the backup application. For example, HP StorageWorks Data Protector
Express calls it a Copy job.
LAN
Switch
Server
Server
Server
Backup Data
Copy Data
Tape Drive
SCSI
Card
HP StorageWorks D2D
Backup System
Figure 58 Archiving to tape
Further information
It is not possible to describe how to carry out this operation because it is controlled solely from the
backup application and different applications operate in different ways. HP provides a number of
white papers that describe how to use this function with specific applications; see
http://www.hp.com/
support . Or refer to the documentation that was supplied with your backup application.
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.
Copy using a tape drive attached to the host 172