Patent ID: 8918392

Claim:
A computer-implemented method for accessing data storage devices, comprising: under the control of one or more computer systems configured with executable instructions, implementing, using one or more resources of the one or more computer systems, a map authority that non-transitively stores at least one data map, the map authority being independent of a client and at least in part thereby enabling fault tolerance with respect to client availability, the client being a virtual computer system instance implemented at least in part with one or more computing resources of a distributed computing system, the at least one data map including information that associates block addresses of the client to one or more locations within a storage system that store a client-attached data volume for the client; upon receiving, by the map authority, a change notification from the client, then at least responding to the change notification by providing the client with a receipt affirmation of the request; when the change notification indicates that the client lacks information in a client data map to locate data within the client-attached data volume of the storage system, then further responding to the change notification by providing, to the client, at least a portion of the data map that enables the client to locate the data within the storage system; and when the change notification includes information indicating that the client entity is requesting a change to the stored data map in response to a change of data location within the client-attached data volume, then further responding to the change notification by updating the stored data map to reflect at least a subset of the change of data location within the client-attached volume.