Remote copy synchronization in disaster recovery computer systems
First Claim
1. A method for performing disaster recovery in a computer system, said method comprising:
- establishing a remote copy pair relationship between a first storage element and a second storage element by designating said first storage element as a primary disk and said second storage element as a secondary disk, wherein said first storage element handles write requests from a host, and data from said write requests are subsequently copied to said second storage element;
in response to a loss of connection from said host to said first storage element, designating said secondary storage element as said primary disk, wherein said second storage element handles write requests from said host;
in response to a reestablishment of said remote copy pair relationship between said first storage element and said second storage element,designating said first storage element as said primary disk and said second storage element as said secondary disk;
merging a recording bitmap of said second storage element with a recording bitmap of said first storage element; and
copying data that are marked as changed in said merged recording bitmap from said second storage element to said first storage element.
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Accused Products
Abstract
A method, storage system, and machine-readable medium for resynchronizing data stored among a first storage element and a second storage element of a remote copy pair of storage elements is disclosed. According to one embodiment, a method is provided which includes detecting a reestablishment of a remote copy relationship between the first and second storage elements and performing a resynchronization operation in response to this detection. Performing the resynchronization operation comprises transmitting data of a second change record associated with the second storage element to the first storage element, combining the second change record with a first change record associated with the first storage element, identifying a data segment of the second storage element utilizing the combined change record, and overwriting data of the first storage element with data of the identified data segment.
25 Citations
12 Claims
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1. A method for performing disaster recovery in a computer system, said method comprising:
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establishing a remote copy pair relationship between a first storage element and a second storage element by designating said first storage element as a primary disk and said second storage element as a secondary disk, wherein said first storage element handles write requests from a host, and data from said write requests are subsequently copied to said second storage element; in response to a loss of connection from said host to said first storage element, designating said secondary storage element as said primary disk, wherein said second storage element handles write requests from said host; in response to a reestablishment of said remote copy pair relationship between said first storage element and said second storage element, designating said first storage element as said primary disk and said second storage element as said secondary disk; merging a recording bitmap of said second storage element with a recording bitmap of said first storage element; and copying data that are marked as changed in said merged recording bitmap from said second storage element to said first storage element. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computer system capable of performing disaster recovery, said computer system comprising:
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means for establishing a remote copy pair relationship between a first storage element and a second storage element by designating said first storage element as a primary disk and said second storage element as a secondary disk, wherein said first storage element handles write requests from a host, and data from said write requests are subsequently copied to said second storage element; means for, in response to a loss of connection from said host to said first storage element, designating said secondary storage disk as said primary disk, wherein said second storage element handles write requests from said host; means for, in response to a reestablishment of said remote copy pair relationship between said first storage element and said second storage element, designating said first storage element as said primary disk and said second storage element as said secondary disk; merging a recording bitmap of said second storage element with a recording bitmap of said first storage element; and copying data that are marked as changed in said merged recording bitmap from said second storage element to said first storage element. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification