Embodiments relate to efficiently replicating data from a source storage space to a target storage space. The storage spaces share a common namespace of paths where content units are stored. A shallow cache is maintained for the target storage space. Each entry in the cache includes a hash of a content unit in the target storage space and associated hierarchy paths in the target storage space where the corresponding content unit is stored. When a set of content units in the source storage space is to be replicated at the target storage space, any content unit with a hash in the cache is replicated from one of the associated paths in the cache, thus avoiding having to replicate content from the source storage space.