Abstract: Example implementations relate to deduplication operations in a storage system. An example includes, in response to initiation of a new backup process to store a first stream of data, initializing a temporary sparse index to be stored in a memory of a deduplication storage system; identifying a cloned portion of the first data stream; identifying at least one container index associated with the cloned portion of the first data stream; identifying a set of hook points included in the at least one container index; and populating the temporary sparse index with a set of entries, the set of entries mapping the identified set of hook points to the at least one container index.

Abstract: Example implementations relate to metadata operations in a storage system. An example includes generating, by a storage controller of a deduplication storage system, a candidate list of container indexes for matching operations of a received data segment, each container index in the candidate list having an associated match cost; identifying, by the storage controller, a journal group associated with a first container index listed in the candidate list; reducing, by the storage controller, a match cost associated with the first container index in response to a determination that the identified journal group is in a modified state; and performing, by the storage controller, the matching operations of the received data segment based at least on the reduced match cost of the first container index.