License and migration of Backup Exec 15

Hallo Sush, thanks so much for your useful information, I'll learn from it. 

However I forgot asking about data migration, I has 02 types of backup with Backup Exec 15 (daily incremental, and weekly full). The total data of weekly backup is about 700GB (user's data only), and it is stored in a IBM Backup Tape 800GB.  

So after the migration of Backup Exec 15 to new File server is completed, I see at least there're 03 ways to restore data from old File server to new File server. (new File server has same computer name, same IP address so that there's no impact to user):

1. Restore data from the nearest Backup Tape into new File server
   
2. Copy the Backup Exec Database (BEDB) from existing Backup Exec Server to the new File Server as this aiticle: https://www.veritas.com/support/en_US/article.100017867.html
3. Use Windows's command "robotcopy" to copy data from old File server to the new File server

As your experience, can you advice which way is the best option in this case, that all data is intact.  

With data capicity is about 700GB, can you estimate the time to complete. Currently Backup Exec 15 takes about 09 hours for a full backup from File server to IBM Tape Drive.

Thanks again for your kind support,