Hi,
More newbie questions 
We are migrating backups to a new setup of Netbackup 7.5, Windows and Unix clients, on two sites with Data Domain storage.
We have installed all large servers (>50gb data) as media servers with the DD Boost plugin to take advantage of de-duplication at source, and these servers have the MUST_USE_LOCAL DRIVE setting applied so they always back themselves up.
We also have two media servers dedicated to backing up all other clients (smaller servers). They are added in the Server list on all small clients.
All media servers write to the same Storage Unit.
Questions is: how do I stop the >50gb media servers with MUST_USE_LOCAL DRIVE from being selected to backup the smaller clients? We had a small client backup that failed last night with "error 59 - access to the client was not allowed". One of the large >50gb media servers we only want to back itself up was selected to backup the small client, and as it is not in the small client's Server list the backup failed.
I do not want all media servers to be allowed to backup all clients. But they do all write to the same Storage Unit. How do I prevent specific media servers from backing up specific clients? I would expect Netbackup not to select a media server for a backup when that media server is not on the client's Server list...!
Thanks