US Patent 9846540 Data durability using un-encoded copies and encoded combinations

Methods and apparatus for data durability using un-encoded copies together with combination encodings are disclosed. Additional storage objects to be included in a durability group with a particular storage object are identified. An encoding of a combination of the particular object and another object of the group is generated. The encoding, as well as an un-encoded copy of the particular object, may be stored at respective nodes of a service. A request to perform a computation operation may be directed to a node with the un-encoded copy. In the event that the un-encoded copy becomes unavailable, a new un-encoded copy may be generated using the encoding.