`find` finds nfs server? I had to run find / -name foo &gt; found.txt and stumbled over the following output:

...
find: /Volumes/MobileBackups/Backups.backupdb/mac/2014-12-17-162004/MacRoot/.DocumentRevisions-V100: Permission denied
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: not responding
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: is alive again
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: not responding
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: is alive again
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: not responding
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: is alive again
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: not responding
nfs server localhost:/FjbUHyS_WAWZQyX9SZ1Wx9: is alive again
find: /Volumes/MobileBackups/Backups.backupdb/mac/2014-12-17-162004/MacRoot/System/Library/DirectoryServices/DefaultLocalDB/Default: Permission denied
...


I'm not using NFS nor have I ever mounted a NFS volume. Where is this coming from?
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