Proposed is a scale-out-type storage system which implements high-availability, high-speed failover. In a scale-out-type storage system, two or more nodes each comprise a cluster controller, a node controller, a plurality of subcluster processes (subclusters and the like) which are processes which execute I/O processing in their own node, which form a subcluster between processes in their own node, and which are synchronized with work-type (active)/standby-type (passive) corresponding processes in the other nodes, and a nonvolatile data store (SODB). The configuration information of the storage system is held partitioned into global configuration information of the SODB and local configuration information and the like of the subclusters and the like, and thereupon the working-type subcluster is capable of executing I/O processing without accessing the SODB.