This reports how often the active and standby appliances in this HA pair check each other's availability, and critically, if the standby fails to reach the active appliance within this interval, it unilaterally promotes itself to active -- making this value the direct control over failover detection speed. Setting this too short risks a false failover (a brief network blip triggering an unwanted split-brain promotion), while setting it too long delays a legitimate failover after a real active-node failure. For example, a check interval of 10 seconds means a genuine active-node crash would be detected and failed over to standby within about 10 seconds, but a transient network hiccup lasting 11 seconds could also incorrectly trigger the standby to take over.