Hi,
The option Process logical volumes for backup one at a time enables the backup of multiple volumes in one job, while creating a snapshot of only one logical volume at a time. To ensure database integrity, or if a volume contains mount points, multiple volumes may need to be snapped at one time.
How to enable single volume snap in Backup Exec 10.x
http://support.veritas.com/docs/269591
What is the intended use of the Open File Option and the Advanced Open File Option?
http://support.veritas.com/docs/263784
Update us on the same and revert for any further Query
Hope this will help you
Thank you
Gauri