The answer is "maybe".
A computer that is acting as a NetBackup media server
and is handling backups of other clients over the LAN needs the NetBackup Enterprise Server license.
A computer that is acting as a NetBackup media server
so that it can only back itself up directly to tape or disk needs the NetBackup Enterprise Client license. This license does
not allow this machine to backup other computers.
The NetBackup Enterprise Client license also activates a number of other features that used to be sold separately:
- FlashBackup, which allows you to do quick(er) whole-volume snapshot-based backups
- Off-host backups, i.e., by mounting an array snapshot of server1's LUN onto server2 so that server2 can do the backup
- SAN Media Server, which allows the client to back itself up directly to tape or disk (as mentioned above)
- SAN Client, which allows the client to back itself up over the SAN to your NetBackup media server (since SAN connections are usually faster than LAN connections)
If you want to use FlashBackup on a particular client machine, that machine needs a NetBackup Enterprise Client license.
However, if you have inherited your NetBackup environment from previous employees it may be hard to tell which machines are licensed for which functions. No NetBackup licenses are directly installed on clients, and media servers only need either the NetBackup Enterprise Server license key or the NetBackup Enterprise Client license key installed on them (this is required by the NetBackup installation script). All of the other license keys are installed on your NetBackup master server, even the NetBackup Enterprise Client license keys for those machines that are not acting as their own media servers.