Storage system with detection and correction of reference count based leaks in physical capacity

A method comprising:

• for a designated group of logical blocks of a content addressable storage system, the designated group comprising a subset of the logical blocks of the content addressable storage system, the subset of logical blocks sharing at least one designated characteristic not shared by other ones of the logical blocks that are not in the subset:
• scanning the logical blocks of the designated group;
• identifying based at least in part on results of the scan at least one physical block that has a discrepancy in its reference count, the reference count indicating a number of the logical blocks that map via their respective content-based signatures to the same physical block;
• and
• modifying the reference count of the identified physical block;
• wherein the method is implemented by at least one processing device comprising a processor coupled to a memory.

A computer program product comprising a non-transitory processor-readable storage medium having stored therein program code of one or more software programs, wherein the program code when executed by at least one processing device causes said at least one processing device:

• for a designated group of logical blocks of a content addressable storage system, the designated group comprising a subset of the logical blocks of the content addressable storage system, the subset of logical blocks sharing at least one designated characteristic not shared by other ones of the logical blocks that are not in the subset:
• to scan the logical blocks of the designated group;
• to identify based at least in part on results of the scan at least one physical block that has a discrepancy in its reference count, the reference count indicating a number of the logical blocks that map via their respective content-based signatures to the same physical block;
• and
• to modify the reference count of the identified physical block.