1
Introduction

Witness

Nowadays, most business operations depend directly on the applications and as a result — on their IT infrastructure. Therefore, providing 24/7/365 uptime and high availability for the applications is a definite way to ensure smooth business operation. Clustering mechanisms are designed to fulfill these goals, however, you need more than half of the nodes to keep the cluster up and running. For a storage cluster, to ensure proper nodes communication, an effective and simple way is to use redundant heartbeat connections. Nonetheless, this is not always an option, especially for geographically distributed clusters. To overcome these limitations, a Node Majority mechanism was introduced.

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Problem

Problems of Clustered Environment

Clustered environment is a unified group of servers (nodes), which serves a single entity to applications and ensures high availability, load balancing, and system scalability. At the same time, in clusters that consist of an even number of nodes, if half of the nodes fail, the failover cluster goes offline, leaving you with no access to data or applications.

In addition, when cluster nodes do not have a proper voting mechanism and lose network communication between each other, a split-brain can occur, leading to data corruption. In this scenario, the only way to perform data recovery is to restore it from backups. In situations, when cluster nodes are distributed between different locations, having redundant network connections between the sites would avoid a single point of failure. However, having several fiber connections is not always possible and often becomes costly.

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Solution

What Is Node Majority and Why Do You Need a Witness Instance

To ensure the availability of a cluster and all of its VMs and applications when there is an even number of nodes, StarWind introduces the so-called Witness node (Node Majority mechanism). Witness node is a separate instance that takes part in quorum voting but requires minimum resources for its deployment. Introducing a Witness node into the StarWind environment ensures that a 2-node cluster will continue running in case any of the nodes fails.

With a separate StarWind Witness node, the possibility of a split-brain is completely eliminated by having another instance that creates quorum and ensures cluster availability. Moreover, a Witness node instance can be deployed in cloud to ensure that a distributed cluster across locations will show maximum uptime numbers and will not require additional hardware to maintain.

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Conclusion

StarWind Ensures High Availability in a 2-Node Cluster with a Witness in the Cloud

StarWind Node Majority Mechanism ensures that the StarWind storage cluster is running with minimum to no downtime at all. Moreover, StarWind provides flexible options for setting up a Witness, including cloud witness, making it exceptionally simple to implement. Whatever your IT infrastructure configuration, StarWind is sure to take its performance to maximum, maintaining high constant application uptime and HA regardless of any disaster.

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What The World Says About Us

StarWind included as Niche Player for the third consecutive time in 2020 Magic Quadrant for HCI



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Success Stories

We were able to build 2-node storage clusters based on virtualization in 19 hypermarkets without any problems and with high cost-efficiency.

Vass Sandor, IT Infrastructure Leader

By being able to virtualize our environment with StarWind, we were able to retire some old hardware, get our services highly available, reduce power consumption and heat in our server closet.

David Gardner, Information Systems Manager

We are satisfied with StarWind. The support is really fantastic. Whenever any issue arises, the response is very prompt, and solution is immediate.

Srinivas Kouda, Company’s Representative

StarWind got us off the clustered environment, which was a big help. So, I could regain control of my storage and reclaim and redistribute the space we desperately needed.

Ryan Fulton, Company’s Representative

Price + Simplicity. StarWind VSAN offers great pricing and allows us to get work done without expensive custom hardware. It also makes getting back online quick and easy after an outage or hardware failure.

Aaron Hayes, IT Manager

We chose StarWind Mainly because of the cost compared to other vendors. Simplicity of setup was also a major factor and I like the fact that you don’t need a vendor certified engineer to perform the installation.

John Harris, Windows System Administrator,
Department of Physics, University of Oxford

Because of recommendations of older colleagues, with StarWind, we got a reliable storage with no additional hardware. There was a need to increase IT infrastructure performance and we saw StarWind as the most cost-effective solution.

Željko Medić, Director of IT Department

StarWind is the best storage product I have ever used! It satisfies and exceeds requirements.

Joe Gursky, Director of IT
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