Delete Symantec Netbackup Disk Pool

The process is :

1. Expire all backup image
2. Delete all image fragment
3. Delete Disk Pool

So fist, issue bpimmedia to get  backup_id
# bpimmedia -L -client [client name]

and then expire the image
# bpexpdate -backupid [backupid] -d 0

Second, delete all image fragment by issue nbdelete
# nbdelete --allvolumes -force

Finally, delete disk pool from Administration console or Administrator JAVA console