While LMDB's internal lock manager relies on pthread mutexes to control write access, and so cannot work across NFS, you can turn that off and use your own lock management instead. This is the approach we used in the LMDB driver for postfix. http://www.postfix.org/LMDB_README.html The OpenLDAP mailing list emails you referenced only talk about LMDB's internal locking. -- hyc