US Patent 11789917 Data deduplication in a storage system

A storage control system receives a first data block to be written to a primary storage, and generates a content signature for the first data block. The storage control system adds a first entry for the first data block into a persistent deduplication database. The first entry comprises a key which comprises the content signature for the first data block. The persistent deduplication database comprises a tree data structure which comprises elements that are configured to store entries for data blocks. The storage control system merges the entries of at least two elements of the tree data structure to generate a set of merged entries which comprises the first entry for the first data block, and a second entry for a second data block, and commences a deduplication process in response to determining that the first entry and the second entry in the set of merged entries have matching keys.