Remote data mirroring system using local and remote write pending indicators
First Claim
1. A remote copy system for automatically providing a remote copy of data from a host computer, said system comprising:
- a first data storage system including a first data storage system controller and at least one first data storage device, the first data storage system controller having a first cache memory, the first data storage system controller receiving the data from the host computer and initially storing the data in the first cache memory and subsequently writing the data into said at least one first data storage device; and
a second data storage system located remote from the first data storage system, the second data storage system including a second data storage system controller and at least one second data storage device, the second data storage system controller having a second cache memory, the first data storage system controller being coupled to the second data storage system controller for copying the data from the first data storage system controller to the second data storage system controller, the second data storage system controller storing the data in the second cache memory and writing the data into said at least one second data storage device to produce the remote copy of the data from the host computer;
the first data storage system controller coordinating and controlling the copying of the data to the second data storage system controller wherein, in response to receipt of the data from the host computer, a first write pending indicator is set to write the data into said at least one first data storage device, and a second write pending indicator is set to copy the data to the second data storage system controller, the first write pending indicator being reset after the data is written to said at least one first data storage device and the second write pending indicator being reset after receiving an acknowledgement back from the second data storage system controller.
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Accused Products
Abstract
A primary data storage system is linked to a geographically remote secondary data storage system for automatically maintaining a remote copy of the data in the primary storage. The primary data storage system controller uses write pending indicators to control and coordinate the remote copy process. In response to receipt of data from the host computer, a first write pending indicator is set to write the data into at least one primary data storage device, and a second write pending indicator is set to copy the data to the secondary data storage system controller. The first write pending indicator is reset after the data is written to the primary data storage device, and the second write pending indicator is reset after receiving an acknowledgement back from the secondary data storage system controller.
490 Citations
20 Claims
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1. A remote copy system for automatically providing a remote copy of data from a host computer, said system comprising:
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a first data storage system including a first data storage system controller and at least one first data storage device, the first data storage system controller having a first cache memory, the first data storage system controller receiving the data from the host computer and initially storing the data in the first cache memory and subsequently writing the data into said at least one first data storage device; and
a second data storage system located remote from the first data storage system, the second data storage system including a second data storage system controller and at least one second data storage device, the second data storage system controller having a second cache memory, the first data storage system controller being coupled to the second data storage system controller for copying the data from the first data storage system controller to the second data storage system controller, the second data storage system controller storing the data in the second cache memory and writing the data into said at least one second data storage device to produce the remote copy of the data from the host computer;
the first data storage system controller coordinating and controlling the copying of the data to the second data storage system controller wherein, in response to receipt of the data from the host computer, a first write pending indicator is set to write the data into said at least one first data storage device, and a second write pending indicator is set to copy the data to the second data storage system controller, the first write pending indicator being reset after the data is written to said at least one first data storage device and the second write pending indicator being reset after receiving an acknowledgement back from the second data storage system controller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A remote copy system for automatically providing a geographically remote copy of data from a host computer, said system comprising:
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a first data storage system including a first data storage system controller and at least one first data storage device, the first data storage system controller having a first cache memory, the first data storage system controller receiving the data from the host computer and initially storing the data in the first cache memory and subsequently writing the data into said at least one first data storage device; and
a second data storage system geographically removed from the first data storage system, the second data storage system including a second data storage system controller and at least one second data storage device, the second data storage system controller having a second cache memory, the first data storage system controller being coupled to the second data storage system controller for copying the data from the first data storage system controller to the second data storage system controller, the second data storage system controller storing the data in the second cache memory and writing the data into said at least one second data storage device to produce the remote copy of the data from the host computer independent of the host computer;
the first data storage system controller coordinating and controlling the copying of the data to the second data storage system controller wherein, in response to receipt of the data from the host computer, when the data is stored into the first cache memory, a first write pending indicator is set to write the data into said at least one first data storage device, and a second write pending indicator is set to copy the data to the second data storage system controller, the first write pending indicator being reset after the data is written to said at least one first data storage device and the second write pending indicator being reset after receiving an acknowledgement back from the second data storage system controller that the data has at least been received by the second data storage system controller;
wherein the first data storage system returns an i/o completion signal to the host computer, and the data is copied to the second data storage system asynchronously from the time when the first data storage system returns the i/o completion signal to the host computer; and
wherein the copying of the data from the first data storage system to the second data storage system is controlled independent of and without intervention from any host computer. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A remote copy system for automatically providing a geographically remote copy of data from a host computer, said system comprising:
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a first data storage system including a first data storage system controller and at least one first data storage device, the first data storage system controller having a first cache memory, the first data storage system controller receiving the data from the host computer and initially storing the data in the first cache memory and subsequently writing the data into said at least one first data storage device; and
a second data storage system geographically removed from the first data storage system, the second data storage system including a second data storage system controller and at least one second data storage device, the second data storage system controller having a second cache memory, the first data storage system controller being coupled to the second data storage system controller for copying the data from the first data storage system controller to the second data storage system controller, the second data storage system controller storing the data in the second cache memory and writing the data into said at least one second data storage device to produce the remote copy of the data from the host computer independent of the host computer;
the first data storage system controller coordinating and controlling the copying of the data to the second data storage system controller wherein, in response to receipt of the data from the host computer, a first write pending indicator is set to write the data into said at least one first data storage device, and a second write pending indicator is set to copy the data to said second data storage system controller, the first write pending indicator being reset after the data is written to said at least one first data storage device and the second write pending indicator being reset after receiving an acknowledgement back from the second data storage system controller that the data has at least been received by the second data storage system controller;
wherein the copying of the data from the first data storage system to the second data storage system is controlled independent of and without intervention from any host computer; and
wherein the first and second write pending indicators are flags in a first table of flag bits maintained by the first data storage system and kept on said at least one first data storage device, and the flags are also kept on said at least one second data storage device in a second table of flag bits maintained by the second data storage system. - View Dependent Claims (20)
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Specification