Example implementations relate to metadata operations in a storage system. An example includes receiving, by a storage controller of a deduplication storage system, a plurality of data streams to be stored in persistent storage of the deduplication storage system; identifying, by the storage controller, a set of journals in a first journal group that are modified during a first backup process; determining, by the storage controller, a count of the set of journals that are modified during the first backup process; comparing, by the storage controller, the determined count to a migration threshold; and migrating, by the storage controller, at least one journal of the set of journals to a second journal group based at least on a comparison of the determined count to the migration threshold.