ELASTICALLY MANAGING CACHE FOR SUB-BLOCK DEDUPLICATION

摘要

A technique for managing cache in a storage system that supports data deduplication renders each of a set of data blocks as multiple sub-blocks and loads a cache-resident digest database on a per-block basis, selectively creating new digest entries in the database for all sub-blocks in a block, but only for blocks that contain no duplicate sub-blocks. Sub-blocks of blocks containing duplicates are excluded. By limiting digest entries to sub-blocks of blocks that contain no duplicates, the storage system limits the size of the digest database, and thus of the cache, while also biasing the contents of the digest database toward entries that are likely to produce deduplication matches in the future.