Compress problem with HPDAT 72 & Arcserve

[GIAT Emirates]

Hi,

I would like to make a backup of my server with an HP DAT 72 and Arcserve V11.5 SP4.

The full backup have to save 42 GO... but all the time, the system asking to put a new tape for full backup. I think, the compression is not available or active even if I check 'compress' on the backup arcserve job option.

Thanks for answer,
Regards

[D Wong]

Hi GIAT Emirates:

Not all data files are compressible. For example, some files are already compressed e.g. *.jpg, *.mpg, *.wzip.

Also, some very small data files are transfered slow to the tape drive and do not get compressed very well. Since, hardware compression depends on the tape drive buffer being full before data can be compressed.

Very large files are easier to compress and databases files that contain empty blank spaces are easier to compress.

So, not all types of data files can give the 2:1 compression ratio. The native capacity of a tape cartridge is more typical of the amount of data that can be stored on the tape cartridge e.g. for a DAT72 it would be more like 36GB. You are getting some compression since you are getting 42 GB's of data per tape cartridge.

Dave W.