From a BigFix perspective, the mount point should be irrelevant as it just knows what server to talk to on what port. If you are not changing the server, then this is all DB2 configuration and I would talk to your DB2 admins.
- Stop BigFix services
- Move database
- Start BigFix services
Depending on how long this will take, you might also want to consider some of the configurations for the agent report times, just like you would do in an upgrade.
I did a quick google search and found the following
If you are stuck, I would open a PMR with IBM and they can help you.