Yes, you need NDMP license for NetWorker to utilize NDMP backup (i.e. direct to tape or over network to DSA). License is per filer and tiered.
Whether backup via CIFS shares is OK depends on your requirements, such as backup window, LAN speed etc. NDMP is likely to be faster even if run over network, due to streaming nature. Also keep in mind, that when backing up via CIFS shares files will be indexed under server that mounted share, not under filer name. But for 120TB of storage I’d seriously consider alternative approach like SnapVault.
You can enable NDMP on filer at any time, it should not affect anything.
To configure NDMP with FC , you may need to do following steps 1. NDMP license for your backup software 2. NDMP enabled on filer 3. Create a NDMP user and encrypt that user ( ndmpd password "user_name" ) -> This is good practice to use a separate user for NDMP other than root , if it is root no need to encrypt it ..
4. You need to have a HBA port on filer , and need to connect the Tape drive with that HBA ( either through FC switch or direct connection, if switch connection need to do zoning as well )
5. once proper connection is done , try sysconfig -t and sysconfig -m , to find the tape drive and media changer information. 6. Once all these done , we are done with netapp, now need to go to the backup master/media server and do the remaining configuration there based on vendor recommendation