Backup file compression

[brianb000]

I am running BackupExec 9 with W2K server. I have a Quantum Super DLT external drive. My tapes are Super DLT I tapes that say 160/320GB. My backup jobs go to about 165 GB and then ask for more media. I am assuming that it is because the tape is full. If you can get 320GB of compressed data on 1 tape, how come I only get around 160GB on a tape? Does anyone know if you have to specify somewhere in BackupExec to compress the data when it is written, or if it does it automatically? I am backing up a lot of Autocad .dwg and similar engineering files. I am not sure if BackupExec has issues with compressing some kinds of data vs. others.

Many thanks.

 

[justin2000]

nothing to do with Be being able to compress it - it's the actual compressiblity of the files you are backing up.

You are getting compression if you are getting above 160gb.
You will never get 320gb on any server - unless of course you are just backing up txt files.

 

[burtonian347]

Justin, I would normally agree with you on this but I have been recently proved wrong on a small LAN which is being backed up using DLT4 20/40 and it is consistantly compressing 1.95/1.00 and backing up 37Mb on the 20/40 tape so I would suggest the problem is more that likely the compression settings in the backup job settings.

 

[justin2000]

If you are using Hardware compression BE does not do anything - the tape drive controls this totally.
Software compression is a different story - BE is using an algorithm from STAC.

burtonian347 - frame that - it doesn't happen often - actually you can call it a rate scenario having a compression ratio of that size whilst backing up a normal server.

 

[burtonian347]

justin2000, I too was dumbfounded at this compression ratio as this is mixed data from several standard apps, but it gives brianb000 hope using the standard BE software compression. The worrying this is that I had to cleanse down from 45Gb to get it to fit and the MD is not considering a new backup solution, lol