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A General Service for Supporting Storage High Availability

IP.com Disclosure Number: IPCOM000249542D
Publication Date: 2017-Mar-03
Document File: 2 page(s) / 47K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to address the problem of configuring and managing a quorum witness solution at a third site by offering it as a service. The approach is to provide a quorum witness service over the cloud or as part of a high availability solution.

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A General Service for Supporting Storage High Availability

High availability solutions often require the use of a 'tie-breaker' or 'quorum witness' in order to make a decision regarding the health of the participants and resolve split-brain situations. This quorum witness is needed in order to resolve situations where each of the participants has a different view of the participant state. This quorum witness typically needs to be located at a third site in order to make sure that it is not affected by the same failures which the high availability solution is set up to handle, and is able to perform its role in the presence of such failures.

Quorum witness solutions are often implemented as an application or a virtual machine (VM). The requirement of having a VM at a third site is not a simple requirement; configuring and managing a VM at a remote location is a relatively complex task requiring time and effort.

To address the problem of configuring and managing a quorum witness solution at a third site, the novel solution is to offer it as a service. The approach is to provide a quorum witness service over the cloud or as part of a high availability solution (e.g., Transparent Failover). The client can register an high availability service on the quorum witness, and henceforth the high availability service instances can update the associated state in the quorum witness and inquire the state of other high availability service instances.

Description of the Quorum Witness Service The quorum witness runs as an application (e.g. VM) in the cloud. The client can register a high availability service to the quorum witness. Quorum witness supplies a set of interfaces that can be used in order to implement high availability in the registered services. Example of possible such interfaces include:

· An interface to register a service to the quorum witness. The service may include multiple cooperating instances. · A service in which an instance can report its health (keepalive). It is expected that the high availability service

sends such a message at set intervals. · A service in which an instant can inquire about the reported health of other instances in the same service. When

receiving such a request, the quorum witness replies with a message which includes the last time a message indicating health was received from the other instances

· A service that can be used by two instances providing high availability for the same storage object (e.g., volume, consistent group of volumes) in order to resolve contention regarding which instance holds the valid image of the storage objec...