A network control system that includes several controllers for managing several switching elements. Each controller includes a network information base (NIB) storage that stores data regarding the switching elements and a secondary storage for facilitating replication of at least a portion of data across the NIB storages of the different controllers. In some embodiments, the primary purpose for one or more of the secondary storage structures is to back up the data in the NIB. In these or other embodiments, one or more of the secondary storage structures serve a purpose other than backing up the data in the NIB. In some embodiments, the NIB is stored in system memory while the system operates for fast access of the NIB records. In some embodiments, one or more of the secondary storage structures are stored on disks which can be slower to access.