A computer system includes a NoSQL/SQL cluster and a distributed storage. In order to make storage target data redundant, a compute node in the NoSQL/SQL cluster instructs other compute nodes in the NoSQL/SQL cluster to write the storage target data into the distributed storage. As regards a file containing the storage target data, the compute node in the NoSQL/SQL cluster deduplicates data in storage apparatuses of a plurality of storage nodes in the distributed storage. The distributed storage performs erasure coding to store a file of the storage target data newly found to be duplicate in deduplication and to store a file of the storage target data not deduplicated in deduplication.