Remote copy for a storage controller with reduced data size
First Claim
1. A remote copy method in a storage system comprising a first storage sub-system configured for communication with a host system and operative to exchange data with the host, a second storage sub-system in data communication with the first storage sub-system, and a third storage sub-system in data communication with the first storage sub-system, the method comprising:
- receiving a first write request from the host to store first data on the first storage sub-system, the first data comprising one or more first blocks of data, each first block of data being associated with a block address;
in response to receiving the first write request, transferring the first data from the first storage sub-system to the second storage sub-system;
receiving a second write request from the host to store second data on the first storage sub-system, the second data comprising one or more second blocks of data, each second block of data being associated with a block address;
in response to receiving the second write request, transferring the second data from the first storage sub-system to the second storage sub-system; and
subsequent to receiving the first write request and the second write request, transferring at least portions of both the first data and the second data to the third storage sub-system, wherein if any of the first data blocks and the second data blocks have the same block address, then for each such pair of data blocks transferring only the second data block.
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Accused Products
Abstract
Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.
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Citations
12 Claims
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1. A remote copy method in a storage system comprising a first storage sub-system configured for communication with a host system and operative to exchange data with the host, a second storage sub-system in data communication with the first storage sub-system, and a third storage sub-system in data communication with the first storage sub-system, the method comprising:
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receiving a first write request from the host to store first data on the first storage sub-system, the first data comprising one or more first blocks of data, each first block of data being associated with a block address; in response to receiving the first write request, transferring the first data from the first storage sub-system to the second storage sub-system; receiving a second write request from the host to store second data on the first storage sub-system, the second data comprising one or more second blocks of data, each second block of data being associated with a block address; in response to receiving the second write request, transferring the second data from the first storage sub-system to the second storage sub-system; and subsequent to receiving the first write request and the second write request, transferring at least portions of both the first data and the second data to the third storage sub-system, wherein if any of the first data blocks and the second data blocks have the same block address, then for each such pair of data blocks transferring only the second data block. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a storage system, a remote copy method comprising:
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receiving a first write request from a host system; storing first data associated with the first write request to one or more disk drives in the storage system; synchronously transferring the first data to a first separate storage system; receiving a second write request from the host system; storing second data associated with the second write request to the one or more disk drives in the storage system; synchronously transferring the second data to the first separate storage system; asynchronously transferring the first and second data to a second separate storage system, including; identifying a pair of data blocks comprising a first block of data from among the first data and a second block data from among the second data that have the same block address; and for each such pair, transferring only one of the first block of data and the second block of data, wherein the block of data that is transferred is the later written block.
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8. A storage system comprising:
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a first storage sub-system configured for communication with a host system and operative to exchange data with the host; a second storage sub-system in data communication with the first storage sub-system; and a third storage sub-system in data communication with the first storage sub-system, the first storage sub-system further operative to; receive a first write request from the host to store first data on the first storage sub-system, the first data comprising one or more first blocks of data, each first block of data being associated with a block address; transfer the first data from the first storage sub-system to the second storage sub-system in response to receiving the first write request; receive a second write request from the host to store second data on the first storage sub-system, the second data comprising one or more second blocks of data, each second block of data being associated with a block address; transfer the second data from the first storage sub-system to the second storage sub-system in response to receiving the second write request; and transfer at least portions of both the first data and the second data to the third storage sub-system, wherein if any of the first data blocks and the second data blocks have the same block address, then for each such pair of data blocks only the second data block is transferred. - View Dependent Claims (9, 10, 11, 12)
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Specification