Failover and load balancing
The proxy server performs load balancing on read requests when high consistency is disabled. When high consistency is enabled, all read and write requests are sent to the primary write server until a failover occurs. If a backend server is unavailable, the operation displays an error. All subsequent operations fail over to the next available server.
The proxy server is aware of all of the replicas of a given partition, and load balances read requests between the online replicas. The proxy server is aware of all of the masters for a given partition, and must use one of these as the primary master. The server that is configured as the primary write server is the primary master. If no primary write server is configured, the first master or peer server is the primary write server. If the primary write server is down, the proxy server is capable of failing over to a backup server (one of the other master or peer servers). If the requested operation cannot be performed by the currently online servers, the proxy server returns an operations error.
- For better performance, all backend servers and the proxy server must be cryptographically synchronized. See Synchronizing two-way cryptography between server instances for information about synchronizing directory server instances.
- Compare operations are not load balanced.
See High consistency and failover for more information.