BACKUP SYSTEM AND BACKUP METHOD

原文（中国語）

A backup system includes a plurality of backup storage devices for storing backup data of backup target data stored in a storage device. The plurality of backup storage devices are classified as backup storage devices belonging to either a primary layer or a secondary layer. In the backup system, the backup target data is backed up by the storage device storing primary backup data, which is backup data of the backup target data, in the backup storage device belonging to the primary layer, and the backup storage device belonging to the primary layer storing secondary backup data, which is backup data of the primary backup data, in the backup storage device belonging to the secondary layer.