1. A virtual storage system comprising: a computing device accessing virtual storage; a plurality of physical storage devices; and a controller in communication with the computing device and the plurality of physical storage, the controller operative to (a) receive a virtual storage access request from the computing device specifying a virtual data access, the virtual data access comprising a plurality of blocks, each of the plurality of blocks associated with one of at least two target physical storage devices, the target physical storage devices comprising at least a subset of the plurality of physical storage devices; (b) determine an access sequence associating one target storage device with each block in the received virtual storage access request; (c) send at least one physical access request to each target storage device; (d) receive at least one error message from at least one target storage device, each error message having an error type; and (e) determine an error response based on the error message type and on the access sequence.