Methods and systems for single instance storage of asset parts

Methods and systems are disclosed that relate to single instance storage of asset parts utilizing a back reference count associated with each asset part. Entries in a journal associated with the asset parts reflect the intention to increment or decrement an asset part's back reference count. The journal may be used to maintain an accurate and reliable reference count for asset parts replicated across multiple disk drives in a distributed storage system, where the replication is structured to reduce the risk of data loss in the event of a disk drive failure. The journal entries may comprise generation numbers used to maintain a back reference count associated with an asset part and to verify a back reference count associated with an asset part.