When using NFS, what technology is used to control locking on the NFS mount?

Oracle VM uses the same DLM (distributed lock manager) for NFS as it does for OCFS2 partitions.

The standard NFS drivers are sufficient to properly lock files in an NFS repository.

Oracle VM ships with the IO-EMU drivers, which provide proper locking for files on an NFS repository.

Oracle VM ships with a DM-NFS server, which runs on the master pool server and handles distributed file locking for an NFS repository.