`find` finds nfs server?
Mac OS is runnning Time Machine backups for you, even if your Time Machine disk is not connected. The backup directory is automatically created and mounted as a network share via NFS at the /Volumes/Mobilebackups directory. 
This is not a backup in the disaster recovery sense, but it will allow you to restore older versions of your files, if you by accident delete a file or regret an edit you did.
Supposedly it will consume a lot of disk space, but only as long as there's at least 20 % free space.

Disable the service with this terminal command if you dont like it:

sudo tmutil disablelocal


To see the NFS path, run the mount command. Optionally "mount -a" to show all volumes.

I believe the physical location of the backups is i /.Mobilebackups but I'm not quite sure.

And according to Apple docs, the find command should take an option "-fstype" with the special value "local" to stay within the same file system, thus avoiding mounted network shares etc. (Not tested - have no access to a Mac system right now).

find / -fstype local -name foo


*)https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/find.1.html