Storage system and control method for managing use of physical storage areas
AssigneeHitachi, Ltd.
InventorsKentaro Kakui, Kyosuke Achiwa
Life of this patent
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Abstract
An object of the present invention is to improve the usage efficiency of a storage extent in a storage system using the Allocation on Use (AOU) technique. A controller in the storage system allocates a storage extent in an actual volume to an extent in a virtual volume accessed by a host computer, detects any decrease in necessity for maintaining that allocation, and cancels the allocation of the storage extent in the actual volume to the extent in the virtual volume based on the detection result.
Claims16
A storage system having a storage device and a controller that controls data input and output to/from the storage device in response to an access request from a host computer connected to the storage system via a communication path, the storage system comprising:
- an actual volume including at least one storage extent in the storage device, and
- a virtual volume accessed by the host computer and including a plurality of virtual extents, at least one storage extent in the storage device being allocated to at least one of the plurality of virtual extents, and at least one storage extent in the storage device not being allocated to at least one of the plurality of virtual extents, wherein
- in response to an access request to a first virtual extent in the virtual volume from the host computer, the controller allocates a first storage extent in the storage device to the first virtual extent if no storage extent in the storage device has been allocated to the first virtual extent, and
- the controller detects any decrease in necessity for maintaining an allocation between the first virtual extent and the first storage extent, and cancels the allocation based on the detection result.
A storage system having a storage device and a controller, that controls data input and output to/from the storage device in response to an access request from a host computer connected to the storage device via a communication path, the storage system comprising:
- wherein the controller allocates a storage extent in the actual volume to an extent in the virtual volume accessed by the host computer in response to the access from the host computer to the virtual volume, predicts extents in the virtual volume that will be subsequently accessed by the host computer, and allocates storage extents in the actual volume to the predicted extents,
- an actual volume including at least one storage extent in the storage device, and
- a virtual volume accessed by the host computer and including a plurality of virtual extents, at least one storage extent in the storage device being allocated to at least one of the plurality of virtual extents, and at least one storage extent in the storage device not being allocated to at least one of the plurality of virtual extents, wherein
- in response to an access request to a first virtual extent in the virtual volume from the host computer, the controller allocates a first storage extent in the storage device to the first virtual extent if no storage extent in the storage device has been allocated to the first virtual extent, and
- the controller predicts extents in the virtual volume that will be subsequently accessed by the host computer, and allocates storage extents in the actual volume to the predicted extents.
A control method in a storage system having a storage device and a controller that controls data input and output to/from the storage device in response to an access request from a host computer connected to the storage system via a communication path, the storage system comprising an actual volume including at least one storage extent in the storage device, and a virtual volume accessed by the host computer and including a plurality of virtual extents, at least one storage extent in the storage device being allocated to at least one of the plurality of virtual extents, and at least one storage extent in the storage device not being allocated to at least one of the plurality of virtual extents, and the control method comprising the steps of:
- in response to an access request to a first virtual extent in the virtual volume from the host computer, the controller allocating a first storage extent in the storage device to the first virtual extent if no storage extent in the storage device has been allocated to the first virtual extent;
- and
- the controller detecting any decrease in necessity for maintaining an allocation between the first virtual extent and the first storage extent, and canceling the allocation based on the detection result.
Dependencies are inferred from the claim text.