Data Protector Express space issue

[timnixon]

I have a HP DAT 72 USB device and am using DP Express software. I am trying to backup files of 60GB to a 72GB tape, but the drive always spits out the tape at around 33GB and askes for new media. I have the software compression set to "software" and the hardware compression set to "compressed". Why won't the 60GB job fit on one tape? And why if I insert a new tape does it tell me it's not the right media?

[Michael Richter]

tim,

at least compression depends on the files you want to compress! Try zipping the files and check the size. ISO-Images, JPG, and other compressed files has a lower compression than eg. textfiles, bmp .. etc
Further i suggest to disable the softwarecompression

rg,mike

[D Lancaster]

Michael is correct. Be sure to disable software compression. Test have shown that having both software and hardware compression enables can actually result in an image larger that either one alone. I generally use the defaults of "Operating System" and Hardware.

But in general, if you are backing up a lot of zip files, iso files, jpeg files or mp3 files you will not get any compression since these formats are already compressed.

Dave

[Tim Nixon]

Thanks for the replies.

I have rar'ed the files in question and they do compress, but not to 2:1. 36GB will compress to 26GB. I guess that 72 figure is a bit misleading. It now becomes tricky to assertain what amount will fit onto one tape - I could use two or more tapes, but them I'd have to get up in the middle of the night to change it - which is exactly what I was trying to avoid.

I will have to keep the files to 36GB to make sure only one tape is used - which then begs the question: are there better solutions than tape for this amount of data?

One other issue I'm having is it seems DPX cannot list what's on a particular tape (if the origional objects are no longer in the catalog - ie if you've lost your catalog). I believe you can import the contents of the tape into the catalog, but if you have named the media something generic like "media1" how would you know which catalog items belonged to that tape? Should I be doing someting in particular to ensure I can identify the improted objects like naming the media very specifically? (Ideally DPX should have a function that lists what's on a tape - like Data Protector)