Ignore this. I got lucky and querying the contents of the volumes in use shows 
only 1 file. I was expecting it to be much larger since these are LTO4 drives 
and can hold lots of data.

From: Dury, John C.
Sent: Wednesday, November 03, 2010 4:37 PM
To: ADSM-L (ADSM-L AT VM.MARIST DOT EDU)
Subject: backup storage pool slow - find offending file

We back all of our nightly data up to an SL 500 LTO4 tape library and then 
during the day, that cloud of data is also copied to another SL500 LTO4 tape 
library at a remote location. The backup storage pool is taking a significantly 
long time to run and appears to be running for a long time because there seems 
to be one file that takes an especially long time to copy from one tape library 
to the other as the backup storage pool is using 3 drives at once and every 
single day, two of the three processes finish and one runs much much longer.  
How can I track this down to find out the file that is causing the backup 
storage pool process to run for such a long time? I'm hoping to narrow it down 
to a file/server to see if it can possibly be excluded or dealt with a 
different way.
Thanks.