DATA Location

Is it possible (and how) to implement a data path on another partition (linux) for an existing system? And then if I do not gain anything, merging it to the production /data path?

Scenario of what I want to achieve (/mnt/data is already running)

/mnt/data resides on an NFS share
Contains over 2 Billion web sites crawled (yeah another search-engine site)

want to add:

/opt/data resides on internal drive
Will contain keyword hash system

Then if I find this does not improve anything - or runs tight (running on IBM Blade center with 76gb internals - so I may be limited), that I can simple shutdown postgres, scp /opt/data/folder/ to the NFS - bring up postgres - fix any conf file, and everything is on the multi-terabyte array?

Checking the pulse of all you speed freaks that just hit the floor because this is on NFS not iSCSI -- don't worry, when this site goes live it will be iSCSI. We have been in private development for 3 years... and the NFS still out runs the Internet connections.