Control device, storage system, and method of controlling a plurality of storage devices

A storage system comprising:

• a plurality of storage devices;
• and
• a control device,
• wherein the control device including
• a memory, and
• a processor coupled to the memory and configured to
• detect that an amount of data written in a first storage device from the plurality of storage devices is larger than a first value, and that the amount of data written in a second storage device from the plurality of storage devices is larger than the first value,
• control a migration of data in a first partial storage area of the first storage device to a second partial storage area of a third storage device included in the plurality of storage devices,
• change an access destination of access to the first partial storage area to the second partial storage area, and
• control a writing of a first part of first data into a remaining partial storage area of the first storage device other than the first partial storage area of the first storage device, and control a writing of a second part of the first data into the second partial storage area of the third storage device, and control a writing of at least a third part of a second data into the second storage device,
• wherein a data volume on the first part of the first data is different from a data volume of the third part of the second data.

A method of controlling a plurality of storage devices, the method comprising:

• detecting that an amount of data written in a first storage device from the plurality of storage devices is larger than a first value, and that the amount of data written in a second storage device from the plurality of storage devices is larger than the first value;
• migrating data in a first partial storage area of the first storage device to a second partial storage area of a third storage device included in the plurality of storage devices;
• changing an access destination of access to the first partial storage area to the second partial storage area;
• writing a first part of first data into a remaining partial storage area of the first storage device other than the first partial storage area of the first storage device, and writing a second part of the first data into the second partial storage area of the third storage device;
• and
• writing at least a third part of second data into the second storage device,
• wherein a data volume on the first part of the first data is different from a data volume of the third part of the second data.