An archival cloud storage service can be created with cost efficient components for large scale data storage and can efficiently use these components. A frontend of the cloud storage service presents an asynchronous storage interface to consuming devices of the cloud storage service. Providing an asynchronous storage service interface avoids at least some of the state data overhead that accompanies a time constrained interface (e.g., a request-response based interface with timeouts in seconds). Backend nodes of the cloud storage service periodically query the frontend servers to select requests that the backend nodes can fulfill. Each backend node selects requests based on backend characteristics information, likely dynamic characteristics, of the backend node. Thus, the storage system underlying the cloud storage service can be considered a self-organizing storage system.