Configuring Clusters, Groups, and Failover
A single instance of MarkLogic Server running on a single machine is called a host. You can configure multiple hosts into a cluster as described in the Scalability, Availability, and Failover Guide. Within a cluster, you can create groups of similarly configured hosts as described in Groups. Different configurations of grouped hosts are useful when different groups of hosts perform different tasks or have different system capabilities.
If a host goes down, its duties can be resumed by another host in the cluster. MarkLogic provides support for failover, which allows the forest to automatically mount to a different host in the event of a forest’s primary host going offline. For details on configuring forests for failover, see High Availability of Data Nodes with Failover and Configuring Shared-Disk Failover for a Forest in the Scalability, Availability, and Failover Guide.