The MIB module manages SME service. SME is an encryption service provided by an encryption node residing on a line card in a storage device. It receives clear-text data from the host, encrypts and then sends it to be written to tape or disk. It does the reverse in the opposite direction so the service is completely transparent to the host. The purpose of this service is to enhance data security in case the tape or disk is lost or stolen.
As with any services important the user requires that provides some level of fault tolerance in a graceful manner. SME provides fault tolerance by allowing encryption nodes to be grouped into a cluster. Nodes in the same cluster immediately take over the work of a failed node so that the user does not experience service disruption.