Environment:

NetBackup 3.2GA running on NT Master/Media Server
NetApp 760 Filer with attached Overland Robotic Library w/ 2 DLT7000 drives 
with compression set to AUTO.

We're not sure, at this point, if compression is actually taking place. It 
seemed like when we backed up 38GB it took one tape plus a little of another. 
Doing the math would imply the first tape only took 35GB. Since the NBU 
compression option is grayed out for an NDMP type class I am assuming that 
there are no settings that have to be done within NBU that would effect the 
hardware compression capabilities of the DLT drives. Is there anything else I 
need to do to insure the data being backed up to these DLT drives is indeed 
being compressed? When a tape is physically mounted in the DLT drives, the 
compression option in the drive configuration panel shows as "ON".

It also occurred to me that maybe none of the 38GB of data was a good 
compression candidate and the DLT did the best it could. I should hopefully 
know more tomorrow. We have added more data to the NetApp device and will do 
the comparison of GB's backed up versus number of tapes mounted. I just thought 
I'd post this now to give anyone who knows more about NDMP to respond.

Regards,
Dennis Dwyer
Tampa Electric Company