In a portal high availability 10.5 scenario, I noticed that when a standby portal machine detects failure in the primary machine, it communicates with the failed primary machine and drops (the standby machine i mean) its "c:\arcgisportal\db" directory and create a new one (may be based on info from the failed primary db folder)!
I noticed that IP communication between the two machines shall continue to exist during fail-over! In my case, if primary machine is shutdown, the standby machine would not startup unless there is access again to the failed machine (even if portal service is down).
Conclusion:
Is portal high availability is only on the service level? That is, if both machines are up (network wise) but one of the portal services is down, then fail-over will take place, while on the other hand, if network access to the primary failed machine is lost, then standby machine will not start?
What is wrong with my configuration?
Here is the error i get when standby machine has no network access to the failed primary machine:
"The portal has been initialized and configured but is not accessible. The internal portal database does not appear to be running or accepting connections. Restart the portal machine or machines and if the problem persists, contact Esri technical support (U.S.) or your distributor (customers outside the U.S.).</Msg>"