Synchronization for initialization of a remote mirror storage facility
First Claim
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1. A method, comprising:
- computing, in a local storage system having a local volume with a plurality of local regions, respective local signatures over the local regions;
creating, in the local storage system, a local bitmap having local bitmap entries, each local bitmap entry indicating a local realization status for an associated local region in a current snapshot, wherein the local realization status is one of a realized status or an unrealized status;
transferring the local bitmap to a remote storage system;
computing, in the remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions, respective remote signatures over the remote regions;
creating, in the remote storage system, a remote bitmap having remote bitmap entries, each remote bitmap entry indicating a remote realization status for an associated remote region, wherein the remote realization status is one of a realized status or an unrealized status;
determining from retrieved entries of the local bitmap and the retrieved entries of the remote bitmap, in the remote storage system, whether the local realization status of a corresponding local region and the remote realization status of a corresponding remote region to the corresponding local region are both the realized status, and if so, transmitting a request to compute the respective local signatures over the corresponding local region;
identifying for a given remote region having a given remote signature and a corresponding local region having a given local signature that the given remote signature does not match the given local signature;
replacing data in the given remote region with data from the corresponding local region; and
using the remote bitmap to identify a realized remote region and using the local bitmap to identify a non-realized local region corresponding to the realized remote region, and releasing the identified realized remote region.
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Abstract
A method includes computing, in a local storage system having a local volume with a plurality of local regions, respective local checksum signatures over the local regions, and computing, in a remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions, respective remote checksum signatures over the remote regions. A given remote region is identified, the given remote region having a given remote signature and a corresponding local region with a given local signature that does not match the given remote signature. The data in the given remote region is then replaced with data from the corresponding local region.
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Citations
15 Claims
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1. A method, comprising:
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computing, in a local storage system having a local volume with a plurality of local regions, respective local signatures over the local regions; creating, in the local storage system, a local bitmap having local bitmap entries, each local bitmap entry indicating a local realization status for an associated local region in a current snapshot, wherein the local realization status is one of a realized status or an unrealized status; transferring the local bitmap to a remote storage system; computing, in the remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions, respective remote signatures over the remote regions; creating, in the remote storage system, a remote bitmap having remote bitmap entries, each remote bitmap entry indicating a remote realization status for an associated remote region, wherein the remote realization status is one of a realized status or an unrealized status; determining from retrieved entries of the local bitmap and the retrieved entries of the remote bitmap, in the remote storage system, whether the local realization status of a corresponding local region and the remote realization status of a corresponding remote region to the corresponding local region are both the realized status, and if so, transmitting a request to compute the respective local signatures over the corresponding local region; identifying for a given remote region having a given remote signature and a corresponding local region having a given local signature that the given remote signature does not match the given local signature; replacing data in the given remote region with data from the corresponding local region; and using the remote bitmap to identify a realized remote region and using the local bitmap to identify a non-realized local region corresponding to the realized remote region, and releasing the identified realized remote region. - View Dependent Claims (2, 3, 4, 5)
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6. Apparatus, comprising:
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a local storage system having a local volume with a plurality of local regions, and a first processor configured to compute respective local signatures over the local regions, and to create a local bitmap having local bitmap entries, each local bitmap entry indicating a local realization status for an associated local region in a current snapshot, wherein the local realization status is one of a realized status or an unrealized status; and a remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions, and a second processor configured to compute respective remote signatures over the remote regions, to create a remote bitmap having remote bitmap entries, each remote bitmap entry indicating a remote realization status for an associated remote region, wherein the remote realization status is one of a realized status or an unrealized status, to identify, for a given remote region having a given remote signature and a corresponding local region having a given local signature that the given remote signature does not match the given local signature, and to replace data in flail the given remote region with data from the corresponding local region, wherein; the second processor is further configured to determine whether the local realization status of a corresponding local region and the remote realization status of a corresponding remote region to the corresponding local region are both the realized status, and if so, to transmit a request to compute the respective local signatures over the corresponding local region, and to use the remote bitmap to identify a realized remote region and using the local bitmap to identify a non-realized local region corresponding to the realized remote region, and releasing the identified realized remote region. - View Dependent Claims (7, 8, 9, 10)
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11. A computer program product, the computer program product comprising:
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a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising; computer readable program code configured to compute, in a local storage system having a local volume with a plurality of local regions, respective local signatures over the local regions; computer readable program code configured to create, in the local storage system, a local bitmap having local bitmap entries, each local bitmap entry indicating a local realization status for an associated local region in a current snapshot, wherein the local realization status is one of a realized status or an unrealized status; computer readable program code configured to transfer the local bitmap to a remote storage system; computer readable program code configured to compute, in the remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions, respective remote signatures over the remote regions; computer readable program code configured to create, in the remote storage system, a remote bitmap having remote bitmap entries, each remote bitmap entry indicating a remote realization status for an associated remote region, wherein the remote realization status is one of a realized status or an unrealized status; computer readable program code configured to determine from retrieved entries of the local bitmap and retrieved entries of the remote bitmap, in the remote storage system, whether the local realization status of a corresponding local region and the remote realization status of a corresponding remote region to the corresponding local region are both the realized status, and if so, transmitting a request to compute the respective local signatures over the corresponding local region; computer readable program code configured to identify for a given remote region having a given remote signature and a corresponding local region having a given local signature that the given remote signature does not match the given local signature; computer readable program code configured to replace data in a given remote region with data from the corresponding local region; and computer readable program code configured to use the remote bitmap to identify a realized remote region and using the local bitmap to identify a non-realized local region corresponding to the realized remote region, and releasing the identified realized remote region. - View Dependent Claims (12, 13, 14, 15)
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Specification