Storage device and storage device control method
AssigneeHitachi, Ltd.
InventorKoichi Ueno
Life of this patent
Estimating the term…
Abstract
A storage device includes plural storage volumes for storing data, a unit for receiving a request for update of the data at a prescribed point in time to be stored in a first of the storage volumes after the prescribed point in time and a unit for storing a duplicate of the data at the prescribed point in time requested to be updated onto a second of the storage volumes, and a unit for storing in an unused storage area of a third of the storage volumes a duplicate of the data at the prescribed point in time requested to be updated according to a state of the second storage volume.
Claims21
A storage device, comprising:
- first, second and third storage volumes for storing data;
- a virtual storage volume which is virtually possessed by the storage device;
- and
- a control unit, wherein
- the control unit includes:
- means for receiving, from an information processing unit, a request for update of the data as the data exists at a prescribed point in time, the updated data to be stored in the first storage volume after the prescribed point in time;
- means for storing a duplicate of the data as the data exists at the prescribed point in time before the update, onto the second storage volume;
- means for storing, in an unused storage area of the third storage volume, a duplicate of the data as the data exists at the prescribed point in time before the update, in response to a determination that the second storage volume has a predetermined state;
- and
- a memory control unit which manages or controls a correspondence between the first, second and third storage volumes and the virtual storage volume, wherein the memory control unit includes information concerning to which one of the first, second and third storage volumes an access is to be made in response to a data I/O request from the information processing unit by reference to the correspondence.
A method of controlling a storage device provided with first, second, and third storage volumes for storing data, comprising:
- receiving, from an information processing unit, a request for update of the data as the data exists at a prescribed point in time, the updated data to be stored in the first storage volume after the prescribed point in time;
- storing a duplicate of the data as the data exists at the prescribed point in time before the update, onto the second storage volume;
- storing the duplicate of the data as the data exists at the prescribed point in time before the update, onto an unused storage area of the third storage volume in response to a determination that the second storage volume has a predeterminated state;
- managing or controlling a correspondence between the first, second, and third storage volumes and a virtual storage volume which is virtually possessed by the storage device;
- and
- controlling to which one of the first, second, and third storage volumes an access is to be made in response to a data I/O request from the information processing unit by reference to the correspondence.
Dependencies are inferred from the claim text.