Storage system and data layout conversion method in storage system

A data layout conversion method in a storage system that is exercised by the storage system including a plurality of nodes,

• wherein the nodes each include
• a storage drive, and
• a processor that processes data that is to be stored in the storage drive in response to an input/output request from a host,
• the processor included in the node creates a redundancy group for forming a redundant configuration of data to be stored in the storage drive, and stores data of the redundancy group in a plurality of the storage drives, and
• when changing a data format of a unit storage area, the processor included in the node
• discards data stored in the unit storage area where part of the data of the redundancy group is stored,
• based on the data of the redundancy group that is stored in an area other than the unit storage area where the data format is to be changed, recovers the discarded data according to a changed data format and re-stores the recovered data in the storage drive, and
• performs an input/output process on the data to be discarded during the data format change, by achieving recovery based on the data of the redundancy group that is stored in an area other than the unit storage area where the data format is to be changed.