| ### replica CDS: a copy of a directory in the CDS namespace. The first instance of a directory in the namespace is the master replica. When CDS managers make copies of the master replica to store in other clearinghouses, all of the copies, including the master replica, become part of the directory's replica set. See also read-only replica. DFS: A read-only copy of a fileset that contains all the data of the source fileset. As a full copy of a fileset, a replica can exist on any aggregate. A replica is different from a clone, which can reside only on the same aggregate as the source fileset. See also clone. Security: An instance of the Security Server and its database. One replica, the master replica, can accept updates and queries to its database. The slave replica can accept only queries. ###