Abstract: A distributed storage system includes a first node group consisting of a plurality of nodes and a second node group consisting of a plurality of nodes. Each of the first node group and the second node group distributes and stores data of an assigned object to a plurality of constituent nodes. The first node group includes at least one first node shared with the second node group and at least one second node not shared with the second node group. The second node group includes the at least one first node and at least one third node not shared with the first node group.

Abstract: A distributed storage system includes a first node group consisting of a plurality of nodes and a second node group consisting of a plurality of nodes. Each of the first node group and the second node group distributes and stores data of an assigned object to a plurality of constituent nodes. The first node group includes at least one first node shared with the second node group and at least one second node not shared with the second node group. The second node group includes the at least one first node and at least one third node not shared with the first node group.

Abstract: A computer system for sharing objects comprises multiple front-end nodes and a back-end node for providing a namespace shared by the front-end nodes. A first front-end node that is any one of the front-end nodes manages local-lock counts for each of objects managed by the first front-end node. The local-lock count is the number of locks taken by operations to the objects including the directory and sub-objects thereof. Every time receiving a request for processing a target object from a client, the front-end node requests the back-end node to lock a parent directory of the target object if the parent directory has not been locked by the back-end node. The front-end node sends a response of the received request to the client regardless of whether or not the parent directory has been unlocked by the back-end node. If the local-lock count of the parent directory is zero, the first front-end node requests the back-end node to unlock the parent directory.

Abstract: A computer system for sharing objects comprises multiple front-end nodes and a back-end node for providing a namespace shared by the front-end nodes. A first front-end node that is any one of the front-end nodes manages local-lock counts for each of objects managed by the first front-end node. The local-lock count is the number of locks taken by operations to the objects including the directory and sub-objects thereof. Every time receiving a request for processing a target object from a client, the front-end node requests the back-end node to lock a parent directory of the target object if the parent directory has not been locked by the back-end node. The front-end node sends a response of the received request to the client regardless of whether or not the parent directory has been unlocked by the back-end node. If the local-lock count of the parent directory is zero, the first front-end node requests the back-end node to unlock the parent directory.