Adjusting High Availability Settings
On the High Availability > Settings page, there are four user- configurable timers that can be adjusted to suit your network’s needs:
•Heartbeat Interval (seconds) – This timer is the length of time between status checks. By default this timer is set to 5 seconds; using a longer interval will result in the SonicWALL taking more time to detect when/if failures have occurred.
•Failover Trigger Level (missed heartbeats) – This timer is the number of heartbeats the SonicWALL will miss before failing over. By default, this time is set to 5 missed heartbeats.This timer is linked to the Heartbeat Interval timer – for example, if you set the Heartbeat Interval to 10 seconds, and the Failover Trigger Level timer to 5, it will be 50 seconds before the SonicWALL fails over.
•Probe Interval – This timer controls the path monitoring speed. Path monitoring sends pings to specified IP addresses to monitor that the network critical path is still reachable. The default is 20 seconds, and the allowed range is from 5 to 255 seconds.
•Election Delay Time – This timer can be used to specify an amount of time the SonicWALL will wait to consider an interface up and stable, and is useful when dealing with switch ports that have a
Synchronizing Firmware
Checking the Synchronize Firmware Upload and Reboot checkbox allows the Primary and Backup SonicWALL security appliances in HA mode to have firmware uploaded on both devices at once, in staggered sequence to ensure security is always maintained. During the firmware upload and reboot, you are notified via a message dialog box that the firmware is loaded on the Backup SonicWALL security appliance, and then the Primary SonicWALL security appliance. You initiate this process by clicking on the Synchronize Firmware button.
Page 32 Configuring a State Sync Pair in NAT/Route Mode