Storage system

A storage system comprising:

• a plurality of physical drives;
• and
• a storage controller that controls an access to the plurality of physical drives, wherein
• the plurality of physical drives form a plurality of parity groups,
• the storage controller is configured to provide a storage area of the plurality of parity groups to a host device as a pool that is a virtual storage area, and
• each of the plurality of physical drives has
• a first state in which an input or an output of data is enabled;
• and
• a second state in which an input and an output of data are disabled, and less power is consumed than power consumed in the first state, and
• the storage controller is configured to:
• cause a first parity group deleted from the pool to transition from the first state to the second state;
• identify a component a type of which is different from a physical drive and that is capable of being transitioned from a normal state to a low-power consumption state by causing the first parity group to transition to the second state and cause the component to transition to the low-power consumption state;
• and
• add the first parity group to the pool after causing the first parity group to transition from the second state to the first state and cause the component to transition to the normal state.