Configuring Hardware Failover On The Primary Sonicwall - SonicWALL SonicOS Enhanced 2.2 Administrator's Manual

Configuring Hardware Failover on the Primary
SonicWALL
Click Hardware Failover on the menu bar to open the Hardware Failover>Settings page.
Hardware Failover Settings
The left half of the SonicWALL Address Settings section displays the primary SonicWALL serial number
and network settings. The right half of the SonicWALL Address Settings section displays the backup
SonicWALL information. To configure Hardware Failover, follow the steps below:
1. Connect the primary SonicWALL and the backup SonicWALL to the network, but leave the power
turned off on both units.
2. Turn on the primary SonicWALL unit and wait for the diagnostics cycle to complete. Configure all of
the settings in the primary SonicWALL before enabling Hardware Failover.
3. Select Enable Hardware Failover.
4. Check the Enable Preempt Mode checkbox if you want the primary SonicWALL to take over from
the backup SonicWALL whenever the primary becomes available (for example, after recovering from
a failure and restarting). If this option is not used, the backup SonicWALL remains the active
SonicWALL.
Alert!
The primary and backup SonicWALL appliances use a "heartbeat" signal to communicate with one
another. This heartbeat is sent between the SonicWALL appliances over the network segment
connected to the interface X5 of the two SonicWALL appliances. The interruption of this heartbeat
signal triggers the backup SonicWALL to take over operation from the primary unit of the Hardware
Failover pair. The time required for the backup SonicWALL to take over from the primary unit depends
on the Heartbeat Interval and the Failover Trigger Level.
5. Enter the Heartbeat Interval time in seconds. Use a value between 3 seconds and 255 seconds. This
interval is the amount of time in seconds that elapses between heartbeats passed between the two
SonicWALLs in the Hardware Failover pair.
6. Enter the Failover Trigger Level in terms of the number of missed heartbeats. Use a value between
2 and 99 missed heartbeats. When the backup unit detects the number of consecutive missed
heartbeats, the backup SonicWALL takes over operation from the primary unit.
Page 138 SonicWALL SonicOS Standard Administrator's Guide