The LifeKeeper Communications Manager (LCM) provides reliable communication between processes on one or more LifeKeeper servers. This process can use redundant communication paths between systems so that failure of a single communication path does not cause failure of LifeKeeper or its protected resources. The LCM supports a variety of communication alternatives including RS-232 (TTY) and TCP/IP connections.
The LCM provides the following:
- LifeKeeper Heartbeat. Periodic communication with other connected LifeKeeper systems to determine if the other systems are still functioning. LifeKeeper can detect any total system failure that is not detected by another means by recognizing the absence of the heartbeat signal.
- Administration Services. The administration functions of LifeKeeper use the LCM facilities to perform remote administration. This facility is used for single-point administration, configuration verification and sanity checking of administrative actions.
- Configuration and Status Communication. The LifeKeeper configuration database (LCD) tracks resource status, availability and configuration through the LCM facilities. These facilities allow the LCD to maintain consistent resource information between the primary and secondary systems.
- Failover Recovery. If a resource fails on a system, the LCM notifies LifeKeeper to recover the resource on a backup system.
In addition to the LifeKeeper services provided by the LCM, inter-system application communication is possible through a set of shell commands for reliable communication. These commands include snd_msg, rcv_msg, and can_talk. These commands are described in the LCMI_mailboxes (1M) manual pages. The LCM runs as a real-time process on the system assuring that critical communications such as system heartbeat will be transmitted.