Patent attributes
A storage system includes a controller that controls switching from a system before switching to a system after switching. The controller includes a check unit that checks whether a connection between the system before switching and the system after switching is enabled, or not, a determination unit that determines whether switching from the system before switching to the system after switching is enabled, or not, a fail-over information migration unit that migrates fail-over information included in the system before switching to the system after switching, a user data migration unit that migrates user data in the system before switching to the system after switching, and a switching execution unit that enables the system after switching to receive I/O from a host.