This article provides the requirements and setup instructions for a Synology High Availability (SHA) cluster.

• SHA requires two identical Synology NAS servers that support Synology High Availability to act as active and passive servers. Click Applied models at the upper-right corner in the Synology High Availability web page for details.
• Incompatible services or packages must be turned off or removed.
• Both servers require the same DSM version.
• The active and passive servers must have the same number of drives with identical drive capacities and positions.
• Both servers must have the same number of LAN ports. If the servers are equipped with additional network interface cards, those network cards will also count as additional LAN ports.
• Both servers must use the same WAN ports and be assigned static IP addresses in the same subnet.
• The two servers must be connected with a cable and use the same network interface. For example, if one end is connected to LAN 1 on one server, then the other end must be connected to LAN 1 on the other server.
• SHA does not support SHR volumes, IPv6, PPPoE, and Wi-Fi. Make sure that the above are all turned off before creating a high-availability cluster.
• If you have purchased a McAfee Antivirus license for a Synology NAS, use that Synology NAS as the active server.

After you have check all of the items listed under Environment, you can launch Synology High Availability to create a cluster. You will be prompted by the wizard to do the following:

1. Specify the assigned IP address for the passive server and specify users belonging to the administrators group as well as their passwords.
2. Select the cluster's Heartbeat connection.
3. Specify the name, network interface, IP address, and the subnet mask of the high-availability cluster.
4. Once the setup is complete, the creation of a high-availability cluster is done and all services can run normally. Failover and switchover operations are available only once the initial data synchronization has been completed.