EBS 7.3 uses only one tape drive for my daily backup

I upgraded EBS from 6.1 to 7.3 recently. and I notice that the daily scheduled backup uses only one of my two tape drives for daily backup. EBS6.1 used all the two tape drives for daily backup.
[200 byte] By [zhou@CMC] at [2007-11-26 10:14:45]
# 1
increase the Max Parrallelism under Devices > Server > Libraries. EBS (Networker) keeps 1 drive aside in case you need to do a restore.
philliphelmling at 2007-7-7 2:06:02 > top of Java-index,Storage Forums,Storage General Discussion...