Method and system for consistent cluster operational data in a server cluster using a quorum of replicas
First Claim
1. A method of operating a server cluster of at least one node, comprising:
- storing cluster operational data on a plurality of replica members that are each independent of any node; and
at one node;
obtaining control of a replica set of a number of replica members;
comparing the number of replica members in the replica set with a total number of replica members configured to operate in the cluster; and
forming the cluster if the number of replica members in the replica set is a quorum of the total number of replica members.
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Accused Products
Abstract
A method and system for increasing the availability of a server cluster while reducing its cost by requiring at a minimum only one node and a quorum replica set of storage devices (replica members) to form and continue operating as a cluster. A plurality of replica members maintain the cluster operational data and are independent from any given node. A cluster may be formed and continue to operate as long as one server node possesses a quorum (majority) of the replica members. This ensures that a new or surviving cluster has a least one replica member that belonged to the immediately prior cluster and is thus correct with respect to the cluster operational data. Update sequence numbers and/or timestamps are used to determine the most updated replica member from among those in the quorum for reconciling the other replica members.
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Citations
49 Claims
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1. A method of operating a server cluster of at least one node, comprising:
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storing cluster operational data on a plurality of replica members that are each independent of any node; and
at one node;
obtaining control of a replica set of a number of replica members;
comparing the number of replica members in the replica set with a total number of replica members configured to operate in the cluster; and
forming the cluster if the number of replica members in the replica set is a quorum of the total number of replica members. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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- 15. A system for providing consistent operational data of a previous server cluster to a new server cluster, comprising, a plurality of nodes, a plurality of replica members, each replica member being independent of any node, at least one replica member having updated cluster operational data stored thereon by a first node including information indicative of a quorum requirement of a number of replica members needed to form a cluster, and a cluster service on a second node configured to 1) obtain control of a replica set of a number of replica members, 2) compare the number of replica members in the replica set with the quorum requirement, and 3) form the new server cluster if the quorum requirement is met by the number of replica members in the replica set.
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21. A method of forming and operating a server cluster, comprising:
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storing cluster operational data on a plurality of replica members, each replica member being independent of any node of the cluster;
arbitrating among a plurality of nodes for exclusive control of a replica set of a number of the replica members; and
at a first node having exclusive control of the replica set;
comparing the number of replica members in the replica set with a total number of replica members configured to operate in the cluster;
forming the cluster if the number of replica members in the replica set is a quorum of the total number of replica members; and
after a failure of at least one replica member, continuing to operate the cluster if the replica members in the replica set remaining operational constitute a quorum of the total number of replica members. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of obtaining representation of a server cluster at a second node that is not presently representing the cluster, comprising:
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storing cluster operational data on a plurality of replica members of a replica set, each replica member being independent of any node of the cluster;
representing the cluster at a first node by obtaining exclusive control of a quorum of the replica members;
defending ownership of the cluster at the first node by regularly persisting exclusive ownership of each of the replica members; and
challenging for exclusive ownership of each of the replica members at the second node, such that if the first node fails and is unable to defend ownership of the replica members, the second node reserves exclusive ownership of a quorum of the replica members and thereby represents the cluster. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. In a server cluster, a method, comprising:
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storing cluster operational data on a plurality of replica members that are independent of nodes of the server cluster;
arbitrating at a first node for control of the plurality of replica members;
determining whether a quorum of replica members is controlled by the first node, and if so, forming a cluster, determining which replica member has the most updated operational data, and replicating the updated operational data to at least one other replica member; and
while a quorum of the replica members continues to be controlled by the first node, operating the server cluster, defending control of the replica members at the first node, and challenging for control of the replica members at a second node. - View Dependent Claims (48, 49)
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Specification