What causes carp to failover

  • What situations would cause a secondary box to take over. I know if network connectivity is lost but what about kernel freezes, hard drive problems, intermittent network issues.

  • Rebel Alliance Developer Netgate

    Each system in a CARP cluster sends out a "heartbeat" with its various settings (vhid, etc) skewed at a specific rate. The master is always broadcasting at the fastest rate, and each other member has a higher skew, based on the "Advertising Frequency" setting for the CARP VIP.

    Anything that would cause the master to stop broadcasting, or cause it to broadcast at a lower rate, would cause a failover. Could be link loss on a NIC, a dead switch port, hard lock, panic, etc, etc.

    Some system problems can also trigger a CARP member to skew itself higher (to advskew 240) if a hardware fault of some kind is detected.

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