or just allowing your hardware to do it? (i.e. do you have compression ticked in the policy)
You must bear in mind, however, that each "type" of data will compress at a different rate & also different programs are able to compress the same data at a different rate (as you appear to have found thru' your testing).
Also note, that if you are trying to compress data that is already compressed (e.g. getting NetBackup to compress already compressed data & then hardware compression during the save) then you could encounter slow backups & the size of the saved data could actually increase.
***EDIT***
See the context sensitive "Help" within policy attributes. There are 3 sections:
Advantages of the Compression attribute Compression reduces the size of a backup by reducing the size of files in the backup. In turn, the smaller backup size decreases the amount of media that is required for storage. Compression also decreases the amount of data that travels over the network as well as the network load.
Disadvantages of the Compression attribute Compression increases the overhead computing on the client and increases backup time due to the time required to compress the files. The lower transfer rate that is associated with compression on the client reduces the ability of some tape devices (notably 8mm) to stream data. The effects of the lower transfer rate causes additional wear on those devices.
The savings in media and network resources, however, still make compression desirable unless total backup time or client computing resources become a problem. If total backup time is a problem, consider multiplexing. The NetBackup multiplexing feature backs up clients in parallel, reducing the total time to back them up.
If compressed data is written to a storage unit that has single-instance store (SIS) capabilities, the storage unit may not be able to use data deduplication on the compressed or the encrypted data. In data deduplication, only one instance of the file is stored. Subsequent instances of the file reference the single file.
How much compression can be expected? The degree to which a file can be compressed depends on the data type. A backup usually involves more than one type of data. Examples include stripped and unstripped binaries, ASCII, and the non-unique strings that repeat. Some data types are more favorable to compression.
(The last part goes on to specify types of data that compress well & those that don't & the effects of compression on them. Plus it lists file types that are not compressed on a UNIX client)
