How Multi-site (WAN) Systems Work
The Apache Geode multi-site implementation connects distinct clusters. The clusters act as one distributed system when they are coupled, and they act as independent systems when communication between sites fails. The coupling is tolerant of weak or slow links between cluster sites. A wide-area network (WAN) is the main use case for the multi-site topology.
A multi-site installation consists of two or more clusters that are loosely coupled. Each site manages its own cluster, but region data is distributed to remote sites using one or more logical connections.
Geode ensures that all copies of a region eventually reach a consistent state on all members and clients that host the region, including Geode members that distribute region events across a WAN.
Each Geode cluster in a WAN configuration uses locators to discover remote clusters as well as local members.
A Geode cluster uses a gateway sender to distribute region events to another, remote Geode cluster. You can create multiple gateway sender configurations to distribute region events to multiple remote clusters, and/or to distribute region events concurrently to another remote cluster.
A gateway receiver configures a physical connection for receiving region events from gateway senders in one or more remote Geode clusters.