A failover node is a special type of a node (report server) that copies the configuration and processes data in the same way as the node to which it is assigned. When the primary or secondary node is unavailable, the user has access to the same data on its failover node.
Remember that any configuration files you manually created and placed on the report server will not propagate to the failover server. For example, if you create a file to import into the report server alert system, the imported configuration will be synchronized with the failover via the database, but the import source file will remain only on the original report server where it was placed.
All failover nodes operate only within a farm concept and require at least one node in an existing cluster or creating a new farm with a failover cluster. The farm creation wizard will guide you in selecting a node for both the primary and the failover. For more information, see Configuring report server farm, step 3.
A failover node is a single report server that is always ready to take over the monitoring responsibilities of the primary or secondary report server to which it is assigned. All failover servers must be of the same type as their main server: only a CAS can be assigned as a failover for another CAS, and only an ADS can be assigned as a failover for an ADS.
Example: report server farm containing failover servers
Configure this special type of report server to provide a backup node for a failover operation. Because each failover node shares configuration settings with the node to which it is assigned, there can be a seamless transition to the failover node if there is a failure.
Deployment with failover nodes
If the primary node fails, the failover primary node will automatically takeover all functions of the primary node. All historical data will be available. The alerts will be generated. Monitoring data will be processed.
A manual process would be required to redirect users to this node and no configuration will be available of that node via the RUM Console.
When the primary node is restored it will take back control from the failover primary node and attempt to process the data collected by data sources during the downtime.
Typically, data retention on data sources oscillate around 8 days. A downtime of longer than 8 days will create a processing hole and the report server will have a gap in the matching days that the data source does not have the data.
If a node fails, the corresponding failover node will automatically takeover all functions of the failed node. All historical data will be available. Monitoring data will be processed.
Deployment without failover nodes
If the primary node fails, users will have no access to the aggregated report server data for the cluster and configuration changes cannot be performed. If the user accesses one of the other nodes in the cluster, they will only be able to view data specific to that node. All alerting functionality will cease.
Processing of data by the whole cluster will be paused until the primary node is restored.
When the primary node is restored, it will reprocess the missing files if they are available in the data sources.
If a node fails, the data displayed on the primary node will not be complete and processing of data by the whole cluster will be paused until the node is restored or the failed node is removed from the farm definition.
When the node is restored, it will reprocess the missing files if they are available in the data sources.
Each failover node is capable of two basic actions: Swap failover with primary and Delete failover.
Swap failover with primary
After the failover is attached to an active (its parent node), you can swap their places, such that the old failover node becomes the new active node and the old active node becomes the new failover node for the new active node. Because the active and the failover nodes have identical configurations and contain the same data, the swap occurs seamlessly and the new active and failover nodes become operational as soon as you publish the configuration.
You can use this option to remove a failover node from its primary node. This action changes the failover node's role to a standalone report server, but it retains the data and options it used while operating as a failover node.