Storage system
AssigneeHitachi, Ltd.
InventorsMasanori Araki, Masatoshi Baba, Yuji Sueoka, Isamu Kurokawa, Hisaharu Takeuchi
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Abstract
For using a plurality of files contained in one logical device with a plurality of processing systems, sharing of a data storage unit among the plurality of processing systems is realized without need for a host processing system to check use states of the files in a server storage unit. Information concerning extent (extent range) of an input/output processing request issued by a host processor is stored in a control memory incorporated in a control unit for allowing the control unit to make decision as to overlap of the extents of the input/output processings to thereby effectuate exclusive control on an extent-by-extent basis.
Claims24
A storage system, comprising a control unit coupled to a plurality of host processors for receiving therefrom a plurality of input/output processing requests each containing a command designating an extent of the input/output processing request to thereby control data transfers between said host processors and a plurality of storage devices on the basis of the commands of said input/output processing requests, said control unit including memories for storing control information for said input/output processing requests on a request-by-request basis, said plurality of storage devices being coupled to said control unit, wherein logical devices are set up across said plurality of storage devices,
- wherein upon reception of a newly issued input/output processing request, said control unit stores the extent of said newly issued input/output processing request in said memory for executing said newly issued input/output processing request provided that any other input/output processing request whose extent overlaps with that of said newly issued input/output processing request is not resident in said memory, whereas when other input/output processing request whose extent overlaps with that of said newly issued input/output processing request is stored in said memory, information indicating that said newly issued input/output processing request is forced to wait for execution thereof is stored in said memory.
A storage system coupled to a plurality of host processors, comprising:
- an external storage;
- and
- a control unit for controlling transfer of information between said host processors and said external storage,
- wherein arrangement is made such that device busy state is prevented from occurrence even when a plurality of commands which do not overlap in respect to extents of input/output processing requests are received from said plurality of host processors for a same logical device.
A storage system coupled to a plurality of host processors, comprising:
- an external storage;
- and
- a control unit for controlling transfer of information between said host processors and said external storage,
- wherein exclusive control for a plurality of input/output processing requests issued for a same logical device from said plurality of host processors is performed by making use of extent of the input/output processing request contained in commands issued by host processors.
A control method in a storage system coupled to a plurality of host processors, said storage system having an external storage device and a control unit for controlling transfer of information between said host processors and said external storage device, said method comprising:
- a first step of issuing, from a host processor, a first command including specification of a logical device and an extent of an input/output request;
- and
- a second step of issuing, from a host processor, a second command including specification of a logical device and an extent of an input/output request,
- wherein even when said first and second steps exist, a device busy state is prevented from occurrence though a same logical device is specified in both the commands unless said extents of said input/output requests of said first and second commands overlap on each other.
A control method in a storage system coupled to a plurality of host processors, said storage system having an external storage device and a control unit for controlling transfer of information between said host processors and said external storage device, said method comprising:
- a first step of issuing, from a host processor, a command for suppressing exclusive control;
- a second step of issuing, from a host processor, a first command including specification of a logical device and an extent of an input/output request;
- and
- a third step of issuing, from a host processor, a second command including specification of a logical device and an extent of an input/output request,
- wherein even when said first, second and third steps exist, a device busy state occurs in spite of that said extents of said input/output requests of said first and second commands do not overlap on each other.
A control method in a storage system coupled to a plurality of host processors and a service equipment, said storage system having an external storage device and a control unit for controlling transfer of information between said host processors and said external storage device, said method comprising:
- a first step of issuing, from a service equipment, a command for suppressing exclusive control;
- a second step of issuing a first command including specification of a logical device and an extent of an input/output request;
- and
- a third step of issuing a second command including specification of a logical device and an extent of an input/output request,
- wherein even when said first, second and third steps exist, a device busy state occurs in spite of that said extents of said input/output requests of said first and second commands do not overlap on each other.
Dependencies are inferred from the claim text.