Patent ID: 8701110

Claim:
A method of updating an extent map, the method comprising: providing in a memory an instance of a first version of the extent map, wherein the instance is referenced by an application, wherein the extent map include entries; storing, at each extent map entry, an offset from the beginning of a physical drive which is identified within said each extent map entry; providing a second version of the extent map; comparing the first version of the extent map with the second version of the extent map; in response to the comparing, determining that there is at least one segment in the second version of the extent map that is different from a corresponding at least one segment in the first version of the extent map; and in response to the determining, updating the first version of the extent map with the at least one segment from the second extent map, wherein the extent map further comprises an overall version indicator and a plurality of segments, wherein the determining comprises comparing a version indicator of at least one of the segments of the first version of the extent map with a version indicator of at least one of the segments of the second extent map.