The “failover after” setting (shown below) in the main Failover Pool configuration is the number of our cloud nodes (datacenters) that must see your server as DOWN before actually failing over.
All of our datacenters monitor your servers all the time. This setting simply allows you to increase the reliability of the results before action is taken. For example, if one of our datacenters is unable to ping your server for a couple minutes but all of the others can, do you want to fail over? The problem may not be yours, and may simply be a network issue somewhere along the line between that one datacenter and your server. It may not impact your customers at all.
By default this setting is set to 2, which is the minimum requirement. It is generally undesirable to trigger a failover when only one location detects your device/server down. But we STRONGLY RECOMMEND that you increase this number to at least 3, but consider something higher. If you really only want to update DNS when your device/server is hard down, the higher this number the better because if all of our monitoring nodes agree, there is a real problem.
If you have any questions or concerns about this setting (or any others, for that matter), reach out to us! We’re here 24×7 to help you.