Abstract: A computer system is coupled to a local storage system and a remote storage system, and comprises a data mover, and a recall size analysis unit. The recall size analysis unit uses a combination of type of the data and size of the data as a retrieval key of an access characteristics to analyze the logs of the same access characteristics and to determine a recall size for each of the access characteristics. The data mover obtains a target data corresponding to the recall size of the access characteristics of the target data from the remote storage system in a case of receiving a read request for the target data that is not stored in the local storage system.

Abstract: A computer system is coupled to a local storage system and a remote storage system, and comprises a data mover, and a recall size analysis unit. The recall size analysis unit uses a combination of type of the data and size of the data as a retrieval key of an access characteristics to analyze the logs of the same access characteristics and to determine a recall size for each of the access characteristics. The data mover obtains a target data corresponding to the recall size of the access characteristics of the target data from the remote storage system in a case of receiving a read request for the target data that is not stored in the local storage system.

Abstract: A file server coupled to a client terminal via a network includes a storage unit for storing received files and a control unit for controlling writing or reading of the files to or from the storage unit, wherein the control unit: performs deduplication by deciding one of files with the same content, which are stored in the storage unit, as a clone source file, and deciding another file as a clone file, which refers to data of the clone source file; and appends data to the clone source file in accordance with an update instruction for the clone file from the client terminal.

Abstract: The file server identifies two or more files, each including duplicated data among a plurality of files that have been stored into the logical storage device as a file group based on the file system information. The file server deletes copies of the duplicated data other than shared data that is one copy of the duplicated data included in the two or more files from the logical storage device. The file server makes a file, which is not a shared file of the file group, referring to the shared file that is a file configured by the shared data. The file server creates a group link that associates the m files that belong to the file group with each other.

Abstract: A high-performance and highly-reliable snapshot management apparatus and method, and a storage system are provided that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a plurality difference volumes are set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volumes and management tables for it are created, with each snapshot being managed according to the management tables. Each management table is divided according to one or more snapshots in accordance with the snapshot creation time. The second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

Abstract: Provided is a method of managing differential snapshots in a storage system, the storage system having a disk drive and a disk controller, the differential snapshot management method including the steps of: providing a storage area of the disk drive as a plurality of logical volumes including an operational volume and a differential volume; storing a time of update for each block in the operational volume; and judging, upon reception of a request to write in a block included in the operational volume, whether to copy data of the block in which requested data is to be written in accordance with the received write request to the differential volume, based on the time of update of the block in which requested data is to be written and a time of creation of the differential snapshot. Accordingly, it is possible to manage the differential snapshot without using a bitmap.

Abstract: A high-performance and highly-reliable snapshot management apparatus and method, and a storage system are provided that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a plurality difference volumes are set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volumes and management tables for it are created, with each snapshot being managed according to the management tables. Each management table is divided according to one or more snapshots in accordance with the snapshot creation time. The second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

Abstract: A high-performance and highly-reliable snapshot management apparatus and method, and storage system are provided that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a plurality difference volumes are set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volumes and management tables for it are created, with each snapshot being managed according to the management tables. Each management table is divided according to one or more snapshots in accordance with the snapshot creation time. The second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

Abstract: Provided is a method of managing differential snapshots in a storage system, the storage system having a disk drive and a disk controller, the differential snapshot management method including the steps of: providing a storage area of the disk drive as a plurality of logical volumes including an operational volume and a differential volume; storing a time of update for each block in the operational volume; and judging, upon reception of a request to write in a block included in the operational volume, whether to copy data of the block in which requested data is to be written in accordance with the received write request to the differential volume, based on the time of update of the block in which requested data is to be written and a time of creation of the differential snapshot. Accordingly, it is possible to manage the differential snapshot without using a bitmap.

Abstract: Proposed are: a high-performance and highly-reliable snapshot management apparatus and method, and storage system, that can prevent the adverse influence of overhead when they retain a multiplicity of snapshots. An operational volume is set in a storage area provided by a first storage apparatus and a difference volume is set in a storage area provided by a second storage apparatus. In response to data writing to the operational volume, difference data is saved in the difference volume and a management table for it is created, and each snapshot is managed according to the management table. This management table is divided according to one or more snapshots in accordance with the snapshot creation time; and if there is more than one management table, the second and any following management tables store specified inheritance information to inherit the content of the preceding management tables.

Abstract: Provided is a snapshot maintenance apparatus and method capable of maintaining a snapshot in a highly reliability manner. In a snapshot maintenance apparatus and method for maintaining an image at the time of creating a snapshot of an operation volume for reading and writing data from and to a host system, a difference volume and a failure-situation volume are set in a connected physical device; and difference data, which is the difference formed from the operation volume at the time of creating the snapshot and the current operation volume, is sequentially saved in the difference volume according to the writing of the data from the host system in the operation volume, and the difference data is saved in the failure-situation volume when a failure occurs in the difference volume.