Abstract: A system is provided in which a server which provides a service to a client terminal, a disk array device upon which data used by the server is stored, and a monitor terminal which detects a bottleneck on the disk array device, are connected via a network. The disk array device or the server calculates performance information including the number of IO requests issued by the server, the times required for processing the IO requests, and a resource utilization ratio for each resource included in the disk array device. The monitor terminal establishes a reference point based upon an average response time obtained by dividing the processing time included in the performance information by the number of the IO requests. And the system is characterized in that a resource is identified as a bottleneck, based upon the resource utilization ratio in a predetermined interval before the reference point.

Abstract: A copying method, disk storage system, and storage medium for copying data from one logical disk to another logical disk, making possible immediate access, in response to a copy command. Copying from a first logical disk to a second logical disk is performed for each area in a copy range, and when there is an access to either logical disk, copying is interrupted. When performing update access of an uncopied area in the first logical disk, the area is copied from the first logical disk to the second logical disk, and then the uncopied area is updated. When performing reference access of an uncopied area in the second logical disk, the corresponding area in the first logical disk is referenced. When performing update access of an uncopied area in the second logical disk, that area in the second logical disk is updated, and copying is prohibited.

Abstract: A copying method, disk storage system, and storage medium for copying data from one logical disk to another logical disk, making possible immediate access, in response to a copy command. Copying from a first logical disk to a second logical disk is performed for each area in a copy range, and where is an access to either logical disk, copying is interrupted. When performing update access of an uncopied area in the first logical disk, the area is copied from the first logical disk to a second logical disk, and then the uncopied area is updated. When performing reference access of an uncopied area in the second logical disk, the corresponding area in the first logical disk is referenced. When performing update access of an uncopied area in the second logical disk, that area in the second logical disk is updated, and copying is prohibited.

Abstract: An input/output scheduling unit forms input/output groups obtained by grouping inputs/outputs to/from a disk apparatus. The input/output scheduling unit defines a ratio of the time during which each input/output group uses the disk apparatus and defines quanta &tgr;1 to &tgr;3 during which each input/output group can continuously use the disk apparatus on the basis of the defined time ratios. When input/output requests are received from a plurality of input/output groups to the disk apparatus, the input/output scheduling unit performs the time-sharing for sequentially switching the allocating times &tgr;1 to &tgr;3 between the input/output groups which competed and using the disk apparatus. Further, an allocating time of the remaining quanta is distributed to the quanta on the shortage side by an allocating time control unit in accordance with a degree of jam of each input/output group.

Abstract: An input/output control device uses all of its cache memory effectively and allows cache memory modules to be added in increments of one. When cache memory included in the input/output control device is operating normally and the input/output control device receives a write request from a processing device, the input/output control device returns a write request completed response after writing data to cache memory as set forth in configuration information included in the input/output control device. The write data in the cache memory is then written to one or more disk devices asynchronously with the write completed response. When there is a problem with a cache memory module, the write data that was to be written to the region controlled by the cache memory module where the problem occurred is divided among the remaining cache memory modules.

Abstract: This invention relates to a copying method, disk storage system and storage medium for copying data from one logical disk to another logical disk, and makes immediate access in response to a copy command possible. Copying from logical disk 1 to logical disk 2 is performed for each area in the copy range, and when there is access, copying is interrupted. When performing update access of an uncopied area in the copy source 1, the area is copied from the copy source 1 to the copy destination, and then the area is updated. When performing reference access of an uncopied area in the copy destination 2, the corresponding area in the copy source 1 is referenced. When performing update access of an uncopied area in the copy destination 2, that area in the copy destination is updated, and copying is prohibited. In this way, it is possible to access the copy source 1 and copy destination 2 while copying is in progress, and it is possible to immediately regard that copying is completed by a copy instruction.

Abstract: A disk time-sharing apparatus is constructed by a disk apparatus having disk drives, an input/output request unit for issuing an input/output request to the disk apparatus, and an input/output scheduling unit. The input/output scheduling unit forms input/output groups obtained by grouping inputs/output sources to/from the disk apparatus, defines a ratio of time during which each input/output group uses the disk apparatus, and decides quanta (allocating time) &tgr;1 to &tgr;3 during which each input/output group can use the disk apparatus continuously on the basis of the defined time ratio. When input/output requests are received to the disk apparatus from a plurality of input/output groups, a time-sharing for using the disk apparatus by switching the allocating time &tgr;1 to &tgr;3 sequentially among the competing input/output groups is performed.

Abstract: An input/output control device uses all of its cache memory effectively and allows cache memory modules to be added in increments of one. When cache memory included in the input/output control device is operating normally and the input/output control device receives a write request from a processing device, the input/output control device returns a write request completed response after writing data to cache memory as set forth in configuration information included in the input/output control device. The write data in the cache memory is then written to one or more disk devices asynchronously with the write completed response. When there is a problem with a cache memory module, the write data that was to be written to the region controlled by the cache memory module where the problem occurred is divided among the remaining cache memory modules.