1. A storage system comprising: a memory storing a first given value as a system data protection level which is set to the storage system; and a processor being configured to logically partition the storage system into a plurality of namespaces, the plurality of namespaces including a first namespace which is set to have a first data protection level with a dynamic value, and a second namespace which is set to have a second data protection level with a second given value, wherein the processor is configured to store first data in the first namespace according to the first given value, as the dynamic value, which is inherited from the system data protection level of the storage system where the first namespace resides, and store second data in the second namespace according to the second given value of the second data protection level.