Abstract: The present invention provides a storage control device which enables the time between failures to prolong as much as possible, though it uses HDD's whose mean time between failures is relatively short. The storage control device controls spindle motors in a manner that a spindle motor is rotated regarding the HDD of data which can access from a host computer and a spindle motor is stopped regarding the HDD of data which are clearly judged that a host computer does not access the data. Whether the host computers can access the HDD or not is judged by the fact that whether the memory region (internal logical volume) provided by the HDD is in mapped to the host logical volume or not which is recognized by the host computer and is able to access thereby.

Abstract: Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.

Abstract: Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.

Abstract: A first storage control device is provided with a virtual LU for showing a logical volume possessed by a second storage control device as if it were its own volume. When data processing requested from a host device is, for example, a specific processing of large load (such as direct backup, logical volume copy, and so on), whether or not the requested processing can be executed by the second storage control device is judged. When it is executable, a command is transmitted to the second storage control device to make it take over the processing.

Abstract: A storage apparatus configuration in a three data center architecture comprises first and second data storage systems, and a remote data storage system. The first data storage systems can copy an image of data stored therein to the remote data storage system without affecting access to storage in the first data storage system. The second data storage system is configured to perform a takeover operation if the first data storage system becomes unavailable.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: Information about remote copy target volumes of other storage systems 2 each having one and the same original volume V1 is registered for each remote copy target volume in advance. When there occurs a failure in a copy source storage system 2, a copy source volume for remote copy target volumes using the storage system 2 having a failure as their copy source is selected newly from the registered copy source volumes, and remote copy is resumed.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: When a bus is used as a data communication channel, data within a disk unit cannot be reproduced or copied into a spare disk while a control unit is making read/write processing based on a request from a host computer, or vice versa. Thus, a loop is constructed by a fiber channel capable of time division multiplex function, and the processing between the disk unit and the spare is performed not through the control unit so that the data within the disk can be copied into the spare while the processing between the host computer and the disk unit is being performed, or both processing operations can be executed in parallel.

Abstract: A method for managing data stored in a hierarchical storage unit of a storage apparatus is disclosed. The storage unit includes a first storage medium having a first access speed and a second storage medium having a second access speed. The first access speed is different from the second access speed. The method comprises determining a first access frequency for information of first type, the first access frequency being associated with a first period of past time. A second access frequency of the information of first type is determined. The second access frequency is associated with a second period of past time and is different than the first access frequency. At least a portion of the information of first type is transferred from the first storage medium to the second storage medium prior to a second period based on the second access frequency determined in the determining-a-second-access-frequency step, the second period corresponding to the second period of past time.

Abstract: Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.