Hierarchical Coherency Log for Managing a Distributed Data Storage System

A system and method for managing distributed coherent datasets using a hierarchical change log is provided. In some embodiments, a distributed storage system is provided that includes a primary storage device containing a primary dataset and a mirror storage device containing a mirror dataset. The mirror dataset includes a coherent copy of the primary dataset. The distributed storage system further includes a hierarchical change log tracking a coherence state for the mirror dataset. The hierarchical change log includes a first sub-log and a second sub-log, and a block range of the first sub-log overlaps a block range of the second sub-log. The hierarchical change log may define a priority relationship between the first sub-log and the second sub-log governing the overlap. The first sub-log and the second sub-log may be independently configured and may be different in one of a representation and a block size.