A system for efficiently distributing messages to a server farm uses a hashing function and a map-based function, or combinations thereof, to distribute messages associated with a processing request. In one implementation, for example, the hashing function has inputs of an identifier for each message in a processing request, and a list of available servers. Upon identifying that any of the servers is unavailable, or will soon be unavailable, the load balancing server uses an alternate map-based assignment function for new requests, and inputs each assignment into a server map. The load balancing server can then use the map or the hashing function, as appropriate, to direct messages to an operating server. Upon receiving an updated list of available servers, the load balancing server can switch back to the hashing function after the map is depleted, and use the updated server list as an argument.