Compression

[Kurl75]

I have an autoloader with 12/24 G tapes in it and am backing up around 13.5G of data. Backup-Exec keeps bombing on the last device at around 12.9 Gigs. it doesnt seem to be compressing even though hardware compression IS on. Any ideas.

-Jeremy

 

[Zelandakh]

compression depends on the sort of files you are backing up. you have an autoloader with 12/24s to back up 13.5GB?

Turn OFF compression (both hardware and software) and run a straight backup to the autoloader using two tapes.

 

[Kurl75]

Thanks for the reply. Here is my problem though, I might not have been clear enough. I have the 6 tape auto loader set up for 1 tape per day and 1 cleaner on Saturday the tapes are 12 gigs but can take 24 gigs compressed. I am backing up 13.5 gigs. This is why i need to have compression done. Im trying not to have to use 2 tapes for 1 day. Any other suggestions

 

[Zelandakh]

Bin some data?? LOL

Have you tried software compression instead of hardware?

 

[Kurl75]

No, I have not. I have read that hardware compression provides the the highest amount. Do I have to set that for every tape used or can I do that globally for the device?

 

[harryrich]

The 2 to 1 compression ratio is an estimate for sources containg a typical mix of data. If the data you are trying to compress already has a high information densitiy, it may not compress at all. Maybe most of your data is already explicity compressed, or in one of standard media formats which includes compression. I've found some well-designed programs and highly normalized databases don't compress much either.

Try people's suggestion for improving compression, but your data just may not fit on s single tape. You might want to go to an alternative backup plan, such as backing up frequently changing data daily and more stable data once per week.

Best of luck.

 

[Kurl75]

thanks for all of the info. The problem was that there was something wrong with the auto-loader itself. Got a replacement and everything has worked out. Thanks again

 

[Tobo]

I have recently had the same problem with compression however I set it to compress software and it has given me more space for the time being. However, after doing so, I now have no catalogues in the restore option and am now unable to restore (have tried cataloging the tape with no success). Anybody any ideas on how to get them back?

 

[Kurl75]

Tobo
I would set the compression back to hardware and then see from the manufacture about the DIP settings on your auto-loader and what they should be. What type of loader are you using?