I was looking at Optimal Service Upgrade from R80.10 to 80.30 (cluster)
"sk107042 ClusterXL upgrade methods and paths " states:
Newly established connections are forwarded to the upgraded cluster members while the cluster members running the previous version continue to inspect the old existing connections.
The more time the upgrade procedure takes, the less old connections exist, and upon stopping the cluster members running the previous version, the connection drop is minimal.
Despite long duration of this upgrade procedure, security and connectivity are fully maintained
But goes against step 4, 8 and 9 of the R80.30 admin guide for OSU
4.Disconnect the upgraded Cluster Members M2 and M3 from their networks.
5.On one of the upgraded Cluster Members (M2), connect the Sync cable.
6.Start the Optimal Service Upgrade - on the Active old Cluster Member M1 and on the connected upgraded Cluster Member M2.
7.Stop the Optimal Service Upgrade - on the Active old Cluster Member M1 and on the connected upgraded Cluster Member M2.
8.Disconnect the Active old Cluster Member M1 from its networks.
9.Reconnect the upgraded Cluster Members M2 and M3 (one by one) to their networks.
That will cause is a complete outage, there are no cable connected.
Did I miss something ?