[Darryl Ramm]

Bad idea in general. Pro Tools 9 has a much older disk IO subsystem than current versions and lacks the disk cache that makes a huge difference.

But you don't actually provide much useful info. What NAS? What client computer/OS? What NAS protocol? (CIFS? Apple? NFS?). What speed drives in it? What physical Ethernet speed? How are you backing up/archiving the sessions on your NAS server? (but all that would help folks to know if what you want to do is just a bad idea or completely crazy).

You are likely creating world of hurt all for solving the inconvenience of dragging and dropping a folder icon too/from a NAS server (and doing that lets you manually control point in time-recovery options, and gives you redundancy of local and NAS storage, so is often a great thing).