In a well-planned SplitSite configuration, a third computer hosts the quorum service. The quorum service processing requirement is small, so any other existing computer or VM that meets all network and operating requirements can host the quorum service. An effective quorum server depends upon the location of the quorum computer within your network.
After you have determined an effective location for the quorum computer (and an alternate quorum computer, if desired) and ensured that the computer meets the requirements of the quorum service, you can create the quorum server.
Locate the first quorum computer in a third site within your network, as
You should connect the quorum computer to an electrical circuit that is different from the electrical circuit that powers node0 or node1. In addition, you should connect the quorum computer to a UPS unit.
If one node shuts down and the VM (AX) on the remaining node cannot reach either the quorum server or its peer, it will shut itself down to avoid the risk of a split-brain condition.
When locating the quorum computer:
See Understanding Quorum's Effect on System Behavior for a description of system behavior and failure modes.
You can add another quorum computer (with its switch) to your system to create an alternate quorum service. The most common use of an alternate quorum server is when, for example, operating system updates are being applied to the preferred quorum computer. When the preferred quorum computer restarts, the alternate quorum computer is selected and no downgrade occurs. When the preferred quorum is recovered, the selection moves back to the original preferred quorum computer.
When creating a second quorum service, you must follow all of the requirements for the network and quorum placement. If both nodes can communicate with each other and with the same quorum server (either the preferred or alternate quorum server), the system can maintain VM redundancy, even if one quorum connection is lost. Preferred quorum server selection occurs when both nodes have access to each other and to the preferred quorum server. Thus, if the preferred quorum service is lost at the same time a node is lost, the remaining node shuts down the VM even if a second, non-preferred quorum service is available. However, if the preferred quorum service is lost before a node is lost, and if both nodes can continue to contact the alternate quorum server, the selection is moved to the alternate quorum server. Fault handling occurs in a context of the selected quorum server only.
If you create an alternate quorum service, you need to add a second quorum IP address when adding the quorum service in the everRun Availability Console.
You can install quorum service software on any general-purpose computer, laptop, or VM that is running the Windows operating system and that meets these requirements:
The computer can continually remain powered on and connected to the network such that the ibiz0 network of the everRun system can always access the quorum server.
The computer has a static IPv4 network address. Do not use DHCP.
The operating system is Windows Server 2016, Windows Server 2012, Windows Server 2008, Windows 7, or Windows 10; Embedded versions of the Windows OS are not supported.
A minimum of 100 MB disk space is available.
Two UDP ports must be open and available for communication between the nodes and the quorum service, including in the firewalls. By default, these ports are 4557 and 4558. To change these ports, see Configuring the Quorum Service Port (on the quorum computer) and Configuring the Quorum Server Within the everRun Availability Console.
After you have determined an appropriate location for the quorum computer, download and install the required software to create the quorum server.
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