Efficient recovery of storage gateway cached volumes

A system, comprising:

• one or more hardware computing devices configured to:
• in response to a determination to bring a storage appliance into a running state after an unplanned shutdown, wherein the appliance is configured to cache a plurality of data chunks of a storage object of a remote storage service,
• read into an in-memory metadata region, from a first metadata location of the appliance, chunk metadata corresponding to a particular data chunk of the plurality of data chunks;
• based at least in part on an analysis of a portion of the chunk metadata, store an indication of a validation requirement for the particular data chunk;
• designate the particular data chunk as being accessible for input/output (I/O) requests after the indication of the validation requirement has been stored;
• and
• in response to receiving, after the designation of the particular data chunk, an I/O request targeted to at least a portion of the particular data chunk, validate at least a portion of the chunk metadata using a different metadata storage location of the appliance, prior to a completion of one or more I/O operations indicated in the I/O request.

A non-transitory computer-accessible storage medium storing program instructions that when executed on one or more processors:

• in response to a determination to bring a storage appliance into a running state after an unplanned shutdown, wherein the appliance is configured to cache a plurality of data chunks of a storage object of a remote storage service,
• read into an in-memory metadata region, from a first metadata location of the appliance, chunk metadata corresponding to a particular data chunk of the plurality of data chunks;
• based at least in part on an analysis of a portion of the chunk metadata, store an indication of a validation requirement for the particular data chunk;
• designate the particular data chunk as being accessible for input/output (I/O) requests after the indication of the validation requirement has been stored;
• and
• in response to receiving, after the designation of the particular data chunk, an I/O request targeted to at least a portion of the particular data chunk, validate at least a portion of the chunk metadata using a different metadata storage location of the appliance, prior to a completion of one or more I/O operations indicated in the I/O request.