lately we had a problem with a storage system (it was out of free space). On the storage of this storage system one of our additional polling engines is installed.
In the period of time where the storage system went down, our main polling engine reported the additional polling engine as "up" (via ICMP), althougt it wasn't reachable or accessible at some times.
In the following screenshot (packet loss chart) you can see that Orion didn't received any ICMP values in the period of time (but it didn't get to 100% packet loss):
Has anybody an explanation for this phenomenon?