A computer controls deduplication of data. The computer generates a hash of a remote data and a hash of a local data. The computer generates a set of unmatched hash data based on a comparison of the hash of the remote data against the hash of the local data. The computer generates a splitting cost that is associated with splitting the set of unmatched hash data. The computer sends a request to a server based on a comparison of the splitting cost to a threshold. The request dictates sending of the remote data to a storage controller.