Troubleshooting
This section includes the following information:
Troubleshooting case: Adjusting time to failover
Time required for traffic to be redirected to the new active appliance varies by your network’s responsiveness to changeover notification and by your configuration. Failover time is a product of HA settings and other factors:
Total failover time = ARP Packet Numbers setting x ARP Packet Interval setting + Network responsiveness + Heartbeat timeout setting
For example, the total time between the first unacknowledged heartbeat and traffic redirection could be up to 5.6 seconds given the following factors:
• Detection Interval is 3 (i.e. 0.3 seconds)
• Heartbeat Lost Threshold is 2
• ARP Packet Numbers is 3
• ARP Packet Interval is 1
• Network switches etc. take 2 seconds to acknowledge and redirect traffic flow
If failover time is unacceptable, you can tune the ARP Packet Numbers and ARP Packet Interval settings.
Troubleshooting case: Both cluster members appear as main
The HA Member table on the System > Config > High Availability page displays cluster status. The HA Role column indicates whether the node is active or passive:
• main—The node in this row is currently active. The active node applies policies to govern the traffic passing to your servers. Also called the primary or main appliance.
• standby—The node in this row is currently passive, and is not actively applying policies. The passive node listens to heartbeat traffic and port monitoring for signs that the main node might have become unresponsive. Also called the secondary or standby appliance.
If both nodes indicate that they are the main:
• Test the cables and/or switches in the heartbeat link to verify that the link is functional.
• Verify that you have selected the heartbeat port or ports in Heartbeat Interface. Make sure that the primary and secondary link is not crossed (that is, the primary heartbeat interface is not connected to the secondary heartbeat interface on the other appliance).
• Verify that the Group ID matches on both appliances.
• Verify that the ports on Port Monitor are linked and up (available).
If the heartbeat link passes through switches and/or routers, you might need to adjust the time required after a reboot to assess network availability before electing the main node.