COOPERATIVE FAULT TOLERANCE AND LOAD BALANCING

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for cooperative fault tolerance and load balancing. In one aspect, a method includes receiving a request from an entity wherein the request includes metadata specifying a plurality of non-responsive servers to which the entity sent the request but that could not process the request; determining that the data processing apparatus is not a current home server for the entity based on information cached in the data processing apparatus, wherein the current home server is a server within a plurality of preferred servers that processes requests for the entity and, in response thereto: assigning the data processing apparatus as the current home server so that the entity will send subsequent requests to the data processing apparatus for processing; and sending a response to the entity.