Cooperative fault tolerance and load balancing

A server comprising:

• a hardware processor;
• and
• a non-transitory computer-readable medium coupled to the processor and having instructions stored thereon, which, when executed by the processor, cause the processor to perform operations comprising:
• accessing, at the server, a homing cache specifying entities for which the server is a current home server;
• identifying an entity specified in the homing cache for which the server is the current home sever but not a primary home server;
• determining whether the primary home server is available;
• in response to determining the primary home server is available:
• sending, to the primary home server, a gravitation request that causes the primary home server, in response to receiving and processing the gravitation request, to assign itself as the current home server of the entity so that the entity will send subsequent requests to the primary home server;
• and
• updating the homing cache to indicate the primary home server is the current home server of the entity;
• and
• in response to determining the primary home server is not available, again determining whether the primary home server for the entity is available after a delay period;
• wherein sending, to the primary home server, the gravitation request comprises:
• determining a current load of the server;
• determining a current load of the primary home server;
• sending the gravitation request to the primary home sever only if the current load of the server is greater than the current load of the primary home server.

A non-transitory computer-readable medium having instructions stored thereon, which, when executed by a processor in a server, cause the processor to perform operations comprising:

• accessing, at the server, a homing cache specifying entities for which the server is a current home server;
• identifying an entity specified in the homing cache for which the server is the current home sever but not a primary home server;
• determining whether the primary home server is available;
• in response to determining the primary home server is available:
• sending, to the primary home server, a gravitation request that causes the primary home server, in response to receiving and processing the gravitation request, to assign itself as the current home server of the entity so that the entity will send subsequent requests to the primary home server;
• and
• updating the homing cache to indicate the primary home server is the current home server of the entity;
• and
• in response to determining the primary home server is not available, again determining whether the primary home server for the entity is available after a delay period;
• wherein sending, to the primary home server, the gravitation request comprises:
• determining a current load of the server;
• determining a current load of the primary home server;
• sending the gravitation request to the primary home sever only if the current load of the server is greater than the current load of the primary home server.