HP D2D .HP D2D Backup System user guide (EH985-90907, March 2011) - Page 118

Figure 7 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 StoreOnce Backup System 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 StoreOnce 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. 118 Copy using a tape device attached to the host