Understanding Failover Groups
Failover Groups are collections of Servers that include Patch Servers, Radio Gateways, and Static Reflectors. Failover Groups do not include Rallypoint Groups or People/Channel Groups.
Note: Instructions for the deployment of Patch Servers, Radio Gateways, and Static Reflectors are covered in the ICE Radio and Telephony Gateway Guide.
Failover Group Purpose
When a Patch Server, Radio Gateway, or Static Reflector, fails or is otherwise disconnected, ICE either terminates the connection or switches to a Standby Server. To ensure ICE switches to a Standby Server, newly added Servers must be added to one or more Server Group(s). Only one Server in a Server Group may be Active. All others should be in Standby mode.
Note: The ICE Technical Operations Guide fully describes interactions between Member Servers in a Server Group. For the purposes of administration, the Active Server in a Group is the Leader unless the Group is in an error state with two Member Servers running as Active. See Failover-Generated Audio Looping.
Important: Deploy at least three servers. It is impossible to prevent servers from active/active or standby/standby states when there are only two servers in a group. A third server is required for elections.
Election Quorum Strategy:
If the active Server in a Failover Group disconnects, the remaining Standby Servers determine which of them become the new active Server through an election process. The results of the election must be valid for another server to take over. a Quorum must be reached between the Standby Servers. Each Failover Group may have its own Quorum Strategy.
The following screenshot shows the Quorum Strategy menu in a Rallypoint Group.
N-1
All but one server must be online for a valid quorum. If there are 3 servers, and 1 is down, a quorum can be reached, but if 2 servers are down, the quorum will fail. This strategy is ensures that decisions are made with a broader consensus, which can enhance the reliability and stability of the system.
All but one server must be online for a valid quorum. If there are 3 servers, and 1 is down, a quorum can be reached, but if 2 servers are down, the quorum will fail. This strategy is ensures that decisions are made with a broader consensus, which can enhance the reliability and stability of the system.
Majority
Requires 50% +1 of the member server be online for a valid quorum. If there are 10 servers, and 4 are down, a quorum may be reached, but if 5 or more are down, the quorum will fail. This strategy provides more flexibility but with a narrower consensus.
Requires 50% +1 of the member server be online for a valid quorum. If there are 10 servers, and 4 are down, a quorum may be reached, but if 5 or more are down, the quorum will fail. This strategy provides more flexibility but with a narrower consensus.
None
No quorum required. As long as one Server is online and running, the Server Group remains active. The number of active Servers in the group is not considered.
No quorum required. As long as one Server is online and running, the Server Group remains active. The number of active Servers in the group is not considered.
Warning: This setting prioritizes the presence of an active server over the potential for the simultaneous activation of more than one server – a highly unstable state. Therefore, this setting may not be ideal for systems that require a high level of consensus and stability.