STORAGE CONTROLLER, CONTROL METHOD OF THE SAME, AND INFORMATION PROCESSING SYSTEM
First Claim
1. A storage controller for storing data that is used by a host device, comprising:
- a first storage area that stores write data sent from the host device;
a second storage area to which a storage content of the first storage area that is obtained at a predetermined time point is copied; and
a controller that manages a position at which a difference in storage contents occurs between the first storage area and the second storage area, by switching a plurality of difference bitmaps for each of a plurality of predetermined periods.
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Accused Products
Abstract
In the storage controller of the present invention, different difference bitmaps are used for predetermined sections respectively, whereby the difference between the primary volume and the base volume is managed for each section, and the data are protected efficiently. The difference between the primary volume and the base volume is managed by using the difference bitmaps that are different for the respective sections. The journal data after a lapse of the targeted protection period are written to the base volume and then discarded. At the time of recovery, the difference bitmaps are merged to create a new difference bitmap, and the difference is copied from the base volume to the primary volume. Thereafter, the journal data up to the designated restoration point are written to the primary volume.
22 Citations
18 Claims
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1. A storage controller for storing data that is used by a host device, comprising:
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a first storage area that stores write data sent from the host device; a second storage area to which a storage content of the first storage area that is obtained at a predetermined time point is copied; and a controller that manages a position at which a difference in storage contents occurs between the first storage area and the second storage area, by switching a plurality of difference bitmaps for each of a plurality of predetermined periods.
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2. A storage controller for storing data that is used by a host device, comprising:
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a first volume that stores write data sent from the host device; a second volume to which a storage content of the first volume that is obtained at a predetermined time point is copied; a third volume that stores journal data items created based on a write request targeted at the first volume; a plurality of first difference bitmaps, each of which manages, for each of a plurality of predetermined sections, a position at which a difference in storage contents occurs between the first volume and the second volume; and a controller for controlling the first volume, the second volume, the third volume, and each of the first difference bitmaps, wherein the controller executes; (1) an initial copy function for storing, in the second volume, the storage content of the first volume that is obtained at the predetermined time point; (2) a journal generating function for generating the journal data items on the basis of write requests sent from the host device and causing the third volume to store the generated journal data items; (3) a difference management function for causing one of the first difference bitmaps, which is selected for the each predetermined section, to store the position at which a difference is generated between the first volume and the second volume, on the basis of the write request issued from the host device after the predetermined time point; (4) a reflection function for reflecting, in the second volume, predetermined journal data items that are obtained after a lapse of a pre-designated targeted protection period, out of the journal data items stored in the third volume; (5) a journal discarding function for discarding the predetermined journal data items reflected in the second volume; and (6) a reusing function for deleting a storage content of a predetermined first difference bitmap having all corresponding journal data items discarded, out of the first difference bitmaps, and reusing thus obtained first difference bitmap as a new first difference bitmap. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for controlling a storage controller for storing data used by a host device, the storage controller comprising:
- a first volume that stores write data sent from the host device;
a second volume to which a storage content of the first volume that is obtained at a predetermined time point is copied;
a third volume that stores journal data created based on a write request targeted at the first volume;
a plurality of first difference bitmaps, each of which manages, for each of a plurality of predetermined sections, a position at which a difference in storage contents occurs between the first volume and the second volume; and
a controller for controlling the first volume, the second volume, the third volume, and each of the first difference bitmaps, wherein the controller executes a first control mode having the steps of;(1S) storing, in the second volume, the storage content of the first volume that is obtained at the predetermined time point; (2S) generating journal data items on the basis of write requests sent from the host device and causing the third volume to store the generated journal data items; (3S) causing one of the first difference bitmaps, which is selected for the each predetermined section, to store the position at which a difference is generated between the first volume and the second volume, on the basis of the write request issued from the host device after the predetermined time point; (4S) reflecting, in the second volume, predetermined journal data items that are obtained after a lapse of a pre-designated targeted protection period, out of the journal data items stored in the third volume; (5S) discarding the predetermined journal data items; and (6S) deleting a storage content of a predetermined first difference bitmap having all corresponding journal data items discarded, out of the first difference bitmaps, and reusing thus obtained first difference bitmap as a new first difference bitmap. - View Dependent Claims (15, 16, 17)
- a first volume that stores write data sent from the host device;
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18. An information processing system, comprising:
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a first volume that stores write data sent from a host device; a second volume to which a storage content of the first volume that is obtained at a predetermined time point is copied; a third volume that stores journal data created based on a write request targeted at the first volume; a plurality of first difference bitmaps, each of which manages, for each of a plurality of predetermined sections, a position at which a difference in storage contents occurs between the first volume and the second volume; and a controller for controlling the first volume, the second volume, the third volume, and each of the first difference bitmaps, wherein the controller executes; (1) an initial copy function for storing, in the second volume, the storage content of the first volume that is obtained at the predetermined time point; (2) a journal generating function for generating journal data items on the basis of the write request sent from the host device and causing the third volume to store the generated journal data items; (3) a difference management function for causing one of the first difference bitmaps, which is selected for the each predetermined section, to store the position at which a difference is generated between the first volume and the second volume, on the basis of the write request issued from the host device after the predetermined time point; (4) a reflection function for reflecting, in the second volume, predetermined journal data items that are obtained after a lapse of a pre-designated targeted protection period, out of the journal data items stored in the third volume; (5) a journal discarding function for discarding the predetermined journal data items reflected in the second volume; and (6) a reusing function for deleting a storage content of a predetermined first difference bitmap having all corresponding journal data items discarded, out of the first difference bitmaps, and reusing thus obtained first difference bitmap as a new first difference bitmap.
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Specification