Patent ID: 7424491

Claim:
A storage system comprising: a plurality of file servers, each of which is installed in a corresponding file interface; a file system configured in a plurality of disks configuring a redundant array of inexpensive disks (RAID), said file system being accessible from each of said file servers; and a shared storage area which is accessible from said file servers, and is used to store logs of said file system and file data by said file servers, wherein each of said file servers is configured to receive an input/output (I/O) request for said file system, store a log and file data in said shared storage area in accordance with said I/O request, and store file data in said plurality of disks in accordance with said I/O request, wherein said logs and file data associated with I/O requests each received at different file servers, wherein said file servers include a managing file server and a plurality of request receiving file servers, wherein when one request receiving file server receives a write request to the file system from a client, the managing file server allocates to the one request receiving file server a log entry area and a file data storing area, the log entry area and the file data storing area being located in said shared storage area, wherein the log entry area is used to store a log, wherein the file data storing area is used to store file data, wherein the one request receiving file server stores file data in the file data storing area, then changes a status of the log in the log entry area to a status indicating that the file data has been stored in said shared storage area, and returns a response to the client, and wherein when the one request receiving file server stores the file data in said plurality of disks, then the one request receiving file server changes the status of the log to a status indicating that the file data has been stored in said plurality of disks.