Microsoft Technology Licensing, LLC

Other

Rod N Gamache

Michael T Massa

Sunita Shrivastava

Gor Nishanov

Norbert Paul Kusters

David Bruce Lomet

Rohit Jain

Philip Alan Bernstein

David Allen Dion

Catharine Van Ingen

John D Vert

Rushabh A Doshi

Luis Felipe Cabrera

Rajsekhar Das

Robert T Short

Glenn R Peterson

Mark H Lucovsky

Philip A Bernstein

Patrick James Helland

Nk Srinivas

Jameel Hyder

Kyle E Brandon

Robert Dale Rinne

Raj Das

Sunita V Nishanov

A method and system for increasing server cluster availability by requiring at a minimum only one node and a quorum replica set of replica members to form and operate a cluster. Replica members maintain cluster operational data. A cluster operates when one node possesses a majority of replica members, which ensures that any new or surviving cluster includes consistent cluster operational data via at least one replica member from the immediately prior cluster. Arbitration provides exclusive ownership by one node of the replica members, including at cluster formation, and when the owning node fails. Arbitration uses a fast mutual exclusion algorithm and a reservation mechanism to challenge for and defend the exclusive reservation of each member. A quorum replica set algorithm brings members online and offline with data consistency, including updating unreconciled replica members, and ensures consistent read and update operations.

Consistent cluster operational data in a server cluster using a quorum of replicas

Volume configuration data management systems and methods are described. A logical volume provider maintains an epoch number on each of the extents comprising a volume. Upon each change in the configuration of the volume, the epoch number on each of the currently online extents is updated. When a volume is discovered and a request is made to bring the volume online, the logical volume provider can compare the epoch numbers on the extents to determine if the volume data is consistent across each of the extents, or if an extent contains stale data due to a transitory outage.

Volume configuration data administration

A method and system for increasing server cluster availability by requiring at a minimum only one node and a quorum replica set of replica members to form and operate a cluster. Replica members, independent from the nodes, maintain cluster operational data. A cluster operates when one node possesses a majority of replica members, which ensures that any new or surviving cluster includes consistent cluster operational data via at least one replica member from the immediately prior cluster. Arbitration provides exclusive ownership by one node of the replica members, including at cluster formation, and when the owning node fails. Arbitration uses a fast mutual exclusion algorithm and a reservation mechanism to challenge for and defend the exclusive reservation of each member. A quorum replica set algorithm brings members online and offline with data consistency, including updating unreconciled replica members, and ensures consistent read and update operations.

Method and system for consistent cluster operational data in a server cluster using a quorum of replicas

Logical volume data structure determining configuration status of logical volume based on comparing values of examined volume epoch identifiers on each on-line extent

A method and system wherein following a partitioning of a server cluster, operational subgroups arbitrate for possession of a quorum resource that determines cluster representation, wherein the arbitration is biased by a relative weight of the subgroup. The weight may be relative to the original cluster weight, or submitted as a bid that is relative to other possible subgroup weights. The biasing gives subgroups that are better capable of representing the cluster an arbitration advantage over lesser subgroups. The biasing weight of each subgroup may be determined by node count and/or by a calculation of the subgroup's resources. The arbitration may be delayed based on the relative weight, or alternatively, the arbitration may comprise a bidding process in which a subgroup's bid is based on the subgroup's relative weight.

System for determining at subgroup of nodes relative weight to represent cluster by obtaining exclusive possession of quorum resource

The invention provides a method and system for arbitrating for ownership of a logical quorum resource, such as a logical quorum volume, comprising one or more physical quorum resources so as to form a storage network having a plurality of storage devices. Arbitration and volume management responsibilities are cleanly divided between cluster management software and volume management software. The cluster management software handles the arbitration process without knowing the details of how the logical quorum resource is formed. The volume management software handles the formation and management of the logical quorum volume without having details of the arbitration process.

Quorum resource arbiter within a storage network

LOGICAL VOLUME CONFIGURATION DATA MANAGEMENT DETERMINES WHETHER TO EXPOSE THE LOGICAL VOLUME ON-LINE, OFF-LINE REQUEST BASED ON COMPARISON OF VOLUME EPOCH NUMBERS ON EACH EXTENTS OF THE VOLUME IDENTIFIERS

A method and system for providing remote access and control of devices such as disks, tape drives and modems across a network. A client driver intercepts I/O requests that are destined for a device which an application essentially considers a local device, such as for purposes of disk mirroring. The client driver queues and dequeues the I/O request, marshals it with header information and data, and sends it as a message to the server over one of possibly multiple connections to the server. A server driver unmarshalls the message, places it in a preallocated buffer as designated by the client, and generates an I/O request therefrom directed to the server device. The server responds with a completion status. The client side manages the server buffers, and the client classifies and partitions large requests into one or more segments that fit the server buffers. Sequential processing also may be ensured. The client also handles cancel operations on the remote device, and the client may also load balance across the multiple paths, by selecting a connection based on criteria including pending message size and dynamic performance measurements of the connections.

Method and system for remote access to computer devices via client managed server buffers exclusively allocated to the client

A method and system for distributing various types of cluster data among various storage devices of a server cluster. Cluster core boot data that is needed to get the cluster up and running is stored on a quorum storage mechanism, separate from cluster configuration data which is stored on lower cost and/or higher performance storage. The quorum storage may be implemented via a quorum of nodes, a single quorum disk or a quorum of replica members. The state of the cluster configuration data, as well as the state of other cluster data, may be stored on the quorum storage, thereby assuring the integrity of the data while providing increased reliability through the use of mirror sets of storage elements or the like for storing that data. Significant flexibility in how a cluster may be configured is achieved, along with improved cluster performance and scalability.

Separately storing core boot data and cluster configuration data in a server cluster

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.

A method and system for selecting a set of systems (nodes) for a server cluster from at least two non-communicating sets of systems. A persistent storage device with cluster configuration information therein is provided as a quorum resource. Using an arbitration process, only one system exclusively reserves the quorum resource. The set with the system therein having the exclusive reservation of the quorum device is selected as the cluster. The arbitration process provides a challenge-defense protocol whereby a system can obtain the reservation of the quorum device when the system that has the reservation fails.

Method and system for quorum resource arbitration in a server cluster

A method and system for transparently failing over a computer name with a legacy application running in a server cluster. When the application is set for failing over in the cluster, the cluster software locates a virtual computer name on which the application is dependent, and associates the virtual name with the application. When the application runs and requests its computer name from the system, the system looks for the virtual computer name, and, if detected, the system returns the virtual computer name to the application as the computer name. The virtual computer name thus moves with the application regardless of the machine on which it is running in the cluster. When the application is not set for failing over in the cluster, the system instead returns the actual machine name.

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Issaquah, WA, United States of America

Rod N Gamache