Storage system and storage control method

A storage system comprising:

• a plurality of storage devices;
• a storage controller configured to control the plurality of storage devices,
• wherein each of the plurality of storage devices is configured to provide a sub logical space to the storage controller and manage correspondence relations between physical addresses and logical addresses in the storage device,
• the storage controller is configured to:
• manage a logical space that is a space based on a plurality of sub logical spaces provided by the plurality of storage devices,
• when first data that is one of a plurality of data in the logical space is exchanged for second data that is one of the plurality of data, make a first determination to determine whether or not the first data and the second data are stored in the same storage device, and
• when a result of the first determination is affirmative, replace, in the storage device, a logical address corresponding to the first data with a logical address corresponding to the second data without changing a physical address of a physical area where the first data is stored and a physical address of a physical area where the second data is stored.