sdlt1 160/320 only backs up 200GB's

[Russ Givens_2]

I have an compaq sdlt1 160/320 GB backup device attached to a Windows 2000 Server. I'm using the appropriate tapes - sdlt1. The backup software is Veritas Backup Exec 8.60 for Windows NT/2000. When I backup I only get about 200GB's onto the tape before it is full. Is there anyway of increasing this. In backup exec I have the job using hardware compression and software compression if hardware is not available, but other than that I don't see of increasing the tapes capacity. Most of the data being backed up is autocad drawings, Microstation drawings, pdf's, word, excel. Any suggestions would be appreciated. Thanks

[Eugeny Brychkov · Accepted solution]

Russ,
the first suggestion is about files you're backing up. Native drive capacity is 160GB, this means that without compression you can store only 160GB of data on it. If drive will achieve 2:1 compression ratio then there could be 320GB of data stored. In your case ratio is 1.25:1. So make sure that your files you're backing up are compressable enough. I know that pdfs are not compressable at all.
Try testing drive's compression using HP LTT http://h18006.www1.hp.com/products/storageworks/ltt/index.html
Eugeny

[Leif Halvarsson_2]

Hi,
Compression ratio is highly data dependent, the 2-1 ratio an average and does apply best to plain text files. I have done some tests with .pdf and .dwg files and got a compression ratio of about 1.3-1 (nearly the same as you).