METHODS AND SYSTEMS FOR IMPLEMENTING SHARED DISK ARRAY MANAGEMENT FUNCTIONS
First Claim
1. A controller device for use as one of a set of caching controller devices connected by a network and sharing access to a redundancy group, comprising:
- an array management function (AMF) providing access to the redundancy group; and
a communications port for coupling to the network,wherein the AMF is a first AMF operative to communicate over the network with the redundancy group and with one or more second AMFs distributed among the caching controller devices and sharing access to the redundancy group, the second AMFs including one or more sharing partners and one or more replication partners, the sharing partners maintaining caches for satisfying read and write requests for data of the redundancy group, the replication partners capable of receiving write data from the first AMF and writing the replicated data to a physical storage device if the controller device fails, at least one of the replication partners also being one of the sharing partners,and wherein the first AMF is further operative, in response to a write request from a host to write data to the redundancy group, to;
(a) send an invalidate request to one or more of the sharing partners, the invalidate request indicating that any copies of the data cached at the sharing partners are stale and are to be invalidated;
(b) safely store the data by a selected one of (i) in the event that write-through caching is employed, writing the data to a physical storage device, and (ii) in the event that write-back caching is employed, replicating the data to one or more of the replication partners; and
(c) return a write acknowledgment to the host only upon safely storing the data.
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Accused Products
Abstract
Multiple Array Management Functions (AMFs) are connected to multiple redundancy groups over a storage area network (SAN), such as a fiber-channel based SAN. The multiple AMFs share management responsibility of the redundancy groups, each of which typically includes multiple resources spread over multiple disks. The AMFs provide concurrent access to the redundancy groups for associated host systems. When a host requests an AMF to perform an operation on a resource, the AMF synchronizes with the other AMFs sharing control of the redundancy group that includes the resource to be operated on, so as to obtain access to the resource. While performing the operation, the AMF send replication data and state information associated with the resource such that if the AMF fails, any of the other AMFs are able to complete the operation and maintain data reliability and coherency.
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Citations
19 Claims
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1. A controller device for use as one of a set of caching controller devices connected by a network and sharing access to a redundancy group, comprising:
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an array management function (AMF) providing access to the redundancy group; and a communications port for coupling to the network, wherein the AMF is a first AMF operative to communicate over the network with the redundancy group and with one or more second AMFs distributed among the caching controller devices and sharing access to the redundancy group, the second AMFs including one or more sharing partners and one or more replication partners, the sharing partners maintaining caches for satisfying read and write requests for data of the redundancy group, the replication partners capable of receiving write data from the first AMF and writing the replicated data to a physical storage device if the controller device fails, at least one of the replication partners also being one of the sharing partners, and wherein the first AMF is further operative, in response to a write request from a host to write data to the redundancy group, to; (a) send an invalidate request to one or more of the sharing partners, the invalidate request indicating that any copies of the data cached at the sharing partners are stale and are to be invalidated; (b) safely store the data by a selected one of (i) in the event that write-through caching is employed, writing the data to a physical storage device, and (ii) in the event that write-back caching is employed, replicating the data to one or more of the replication partners; and (c) return a write acknowledgment to the host only upon safely storing the data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of maintaining data coherency across a set of caching controller devices connected by a network and sharing access to a redundancy group, comprising:
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receiving, at a first array management function (AMF) of one of the caching controller devices, a write request from a host to write data to the redundancy group, wherein the first AMF communicates over the network with the redundancy group and with one or more second AMFs distributed among the caching controller devices and sharing access to the redundancy group, the second AMFs including one or more sharing partners and one or more replication partners, the sharing partners maintaining caches for satisfying read and write requests for data of the redundancy group, the replication partners capable of receiving write data from the first AMF and writing the replicated data to a physical storage device if the one caching controller device fails, at least one of the replication partners also being one of the sharing partners; and in response to the write request; (a) sending an invalidate request to one or more of the sharing partners, the invalidate request indicating that any copies of the data cached at the sharing partners are stale and are to be invalidated; (b) safely storing the data by a selected one of (i) in the event that write-through caching is employed, writing the data to a physical storage device, and (ii) in the event that write-back caching is employed, replicating the data to one or more of the replication partners; and (c) returning a write acknowledgment to the host only upon safely storing the data. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification