If any part of the serial console data path is unreliable or goes out of service, users who have a serial (RS-232 TTY) console can experience severe problems with LifeKeeper service. During operation, LifeKeeper generates console messages. If your configuration has a serial console (instead of the standard VGA console), the entire data path from LifeKeeper to the end-user terminal must be operational in order to ensure the delivery of these console messages.
If there is any break in the data path—such as terminal powered off, modem disconnected, or cable loose—the Linux STREAMS facility queues the console message. If the STREAMS queue becomes full, the Unix kernel suspends LifeKeeper until the STREAMS buffer queue again has room for more messages. This scenario could cause LifeKeeper to HANG.