Find out where a mount point is physically located?

[Matty Sarro]

Greetings everyone!
I'm hoping this isn't too noobish of a question.
Right now I am working on a server that was configured to a vendor's specs.
The vendor then came on site, and deployed their software onto the server.
However, there were some extra partitions that we'd created for the
installation and I'm not sure that they were actually used. In / there is
now a mount point called /u1. Is there any way that I can correlate that
back to a particular device on the system? I tried df -h and it isn't really
helping.
-Matthew