Patent ID: 7873878

Claim:
A data storage method comprising: storing first data in at least a first data chunk in response to a write request to store the first data on a first disk drive, wherein the first data chunk is a logical representation of one or more sectors on at least the first disk drive in a storage system; storing first metadata, associated with the first data, in at least a first appendix in response to the same write request, wherein the first appendix is a logical representation of a sector region on at least the first disk drive in the storage system, and wherein the first metadata comprises first atomicity metadata (AMD) and first validity metadata (VMD) associated with the first data; and storing one or more copies of the first VMD for the first data in one or more low latency non-volatile storage (LLNVS) devices in response to the same write request, so that when an error associated with content in the first chunk or the first appendix is detected during a read request for the first data, the copy of first VMD stored in the LLNVS device can be accessed with a low level of latency for the purpose of comparison with the first VMD stored in the first appendix to determine whether the data written during the write request is the same as the data read during the read request, wherein said storing of the first data, the first metadata and the one or more copies of the first VMD is performed prior to retrieval of the first metadata from the first appendix, wherein the retrieval is performed subsequent to said write request.