Storage system and control method of storage system

A storage system comprising:

• a plurality of nodes each including a storage device that physically stores data and a storage controller, wherein the storage controller in an active state uses a storage area of the storage device to form a virtual volume, provides the virtual volume to a host, and processes data input and output to and from the storage device through the virtual volume that the storage controller is responsible for,
• the storage controller in the active state and the storage controller in a standby state that takes over a process of the storage controller in the active state through failover, the storage controllers being arranged in different nodes, form a redundancy group,
• user data input and output by the storage controller in the active state is stored in the storage device of the node,
• redundant data of the user data is stored in the storage device of the node different from the user data, and the storage controller in the standby state changes to the active state and uses the redundant data to input and output data when the failover is performed,
• the user data is stored in one or a plurality of the nodes, and
• the redundant data regarding the redundancy group is distributed and stored in a larger number of nodes than the user data.

A control method of a storage system executed by the storage system including a plurality of nodes each including a storage device that physically stores data and a storage controller, the method comprising:

• by the storage system,
• using the storage controller in an active state to form a virtual volume by using a storage area of the storage device, provide the virtual volume to a host, and process data input and output to and from the storage device through the virtual volume that the storage controller is responsible for;
• using the storage controller in the active state and the storage controller in a standby state that takes over a process of the storage controller in the active state through failover, the storage controllers being arranged in different nodes, to form a redundancy group;
• storing, in the storage device of the same node, user data input and output by the storage controller in the active state;
• and
• storing redundant data of the user data in the storage device of the node different from the user data, and when the failover is performed, changing the storage controller from the standby state to the active state and using the storage controller to input and output data with use of the redundant data, wherein
• the redundant data regarding the redundancy group is distributed and stored in a plurality of nodes.