Over time I've tried several backup options and in the end I found using tar to a backup drive and then ssh to a backup server with both disk and tape backup was the least worry path. I now have four levels of failure before loosing data. (RAID to local IDE to backup server IDE and TAPE.)
Using NFS was an idea until I reviewed the security track of NFS - too much can go wrong. Only if there was no Internet access would I consider it. It's bad enough that users browse on windows boxes. I don't need that headache.