> input on switching that to NT with compression Directives

Compression in this case is done on the client. It exacts a toll in terms of 
the client CPU and memory. The advantage is that it sends less data over the 
network, so it might make sense to use it if your network is very slow or very 
congested. If you have a gigabit network and do your backups when network 
traffic is light, a compression directive will probably make things worse 
rather than better.

> why [is] a 3TB LTO-5 tape is showing full after 1800 GB?

Frank is on the right track. There's probably some sort of hardware error 
involved. Check your server's hardware logs to see if there are any tell-tale 
messages. Also look in the daemon log to see if there are any NetWorker errors 
logged at the time the tapes are reported as full.

HTH,

Conrad Macina