Patent ID: 7185265

Claim:
A data storing method for a storage system having a storage for storing data inputted from an external device and outputting stored data to the external device, comprising the steps of: temporarily storing data, which is to be stored in said storage, into a cache memory, said data being inputted and outputted between said storage system and an external device connected to said storage system; writing said data that is stored in said cache memory into a first area of said storage in a form of a first redundancy level; detecting a predetermined condition with respect to a frequency of input/output between said storage system and said external device; in response to detection of said predetermined condition, writing the data which are stored in the first area into a second area of said storage in a form of a second redundancy level, and after storing said data into the second area, making said data in the first area invalid, thereby releasing said first area for a subsequent write process.