What is server clustering?

A server cluster is a collective group of servers distributed and managed under a single IP address. Each server functions as a node with its own storage (hard drive), memory (RAM), and processing (CPU) resources. By distributing computational resources across multiple interconnected servers, clustering creates an infrastructure resilient enough to withstand hardware failures, balance complex workloads, and provide near-continuous system availability.

We’re going to dive deep into the architecture of server clustering and its strategic implications for businesses seeking to build a more efficient digital infrastructure.

How does server clustering work?

Server clustering is a complex system of interconnected computing resources designed to enhance performance, reliability, and scalability. Distributing workloads and providing redundant capabilities transforms individual servers into a powerful, unified infrastructure.

At the heart of server clustering are nodes—individual servers with independent memory, storage, and CPU resources. What binds them together is a shared operating system image and core applications, creating a cohesive computational environment.

Typically, not all nodes within the cluster operate at the same time. One will be operational, while the rest of the nodes within the server cluster will be in standby mode, ready to take over instantaneously if the active node experiences performance degradation or complete failure. This balancing of the cluster’s workload makes website or app downtime virtually non-existent.

Why are server clusters deployed?

Businesses deploy server clusters to mitigate:

1. Hardware failures: To prevent a complete system shutdown when physical server components malfunction.
2. Application failures: To ensure continuous operation when specific applications encounter issues.
3. Site outages: To maintain system accessibility during unexpected network or infrastructure disruptions.

For instance, a two-node cluster configuration means that if one physical server crashes, the second will immediately take over, keeping downtime minimal. This approach is crucial because downtime can result in lost productivity, revenue reduction, reputation damage, and potential compliance violations.

Cluster server architecture is also ideal for businesses suffering from performance degradation. It lets them split off the database server to enable fast and uninterrupted performance for high-volume workloads.

Types of server clusters

Your server cluster configuration directly impacts an organization’s IT infrastructure effectiveness. There are three types of server clusters and the type you choose depends on your business objectives and infrastructure needs. Let’s explore each type in depth.

Single quorum clusters

These offer the ability to host multiple cluster configurations within a single device, which is beneficial for organizations seeking to consolidate their server infrastructure while maintaining flexible computational capabilities.

Using advanced bus or cluster array technologies, they offer benefits like centralized management of multiple cluster instances, efficient resource allocation, simplified infrastructure complexity, and reduced physical hardware footprint. 

Majority node set clusters

This cluster is focused on system reliability, where it remains operational as long as a majority of nodes are functional. This means that if a cluster has five nodes, at least three must remain operational to maintain system functionality, ensuring continuous operation even when some nodes experience issues. Key characteristics include dynamic node participation, enhanced system integrity, automatic failover mechanisms, and resilience against partial system failures.

Single node clusters

While it might seem counterintuitive, single node clusters serve a specific and valuable purpose in certain computational environments. These minimal clustering configurations are designed for small-scale infrastructure deployments, environments with limited computational needs, initial stages of infrastructure development, and cost-sensitive organizations.

Despite their simplicity, single node clusters offer basic redundancy and can provide a foundational step towards more complex clustering strategies.

Cluster architecture configurations

1. High availability (HA) server clusters

High availability clusters are an optimal choice for high-traffic websites that need reliability and scalability. For example, you may use HA clusters for online shops or applications that need optimal, continuous performance from their critical systems. They also let you avoid single points of failure since they are built on redundant hardware and software and are critical for load balancing, system backups, and failover.

HA clusters have two architecture types: active-active and active-passive. An active-active cluster means all nodes work simultaneously to balance loads. In contrast, an active-passive architecture means a primary node handles all workloads while a secondary node remains on standby for downtime, ready to take over if a component crashes. Although more effective, the active-active configuration typically costs more since all nodes within the system must stay active, making the active-passive configuration a cost-effective choice.

2. Load balancing clusters

Load balancing clusters are server farms that distribute user requests to multiple active nodes and divide workloads between servers. The main benefits include maximum utilization of resources and workload distribution, accelerating operations, scalability, and ensuring redundancy, often required in applications such as data centers and telecom companies.

In active-active configurations, load balancers respond to different requests and distribute them to independent servers, whereas, in an active-passive (or hot-standby) configuration, the load balancer monitors nodes’ availability, suspending traffic to non-operational nodes.

3. High-performance clusters

High-performance clusters, also known as supercomputers (as they’re made up of many computers connected to the same network), offer higher performance, capacity, and reliability, and are used by businesses with resource-intensive workloads such as Internet of Things (IoT) and Artificial Intelligence (AI) technology. They process large amounts of real-time data to power complex projects such as live streaming, storm prediction, and patient diagnosis. 

4. Clustered storage systems

Clustered storage consists of at least two storage servers that help you increase your system’s performance, node space input/output (I/O), and reliability. Depending on business requirements and storage demands, you can opt for a tightly or loosely coupled architecture.

A tightly coupled architecture is directed at primary storage and separates data into small blocks between nodes. In contrast, a self-contained, loosely coupled architecture offers more flexibility but doesn’t store data across nodes, which could affect performance. Unlike tightly coupled architecture, you can’t scale with new nodes.

Benefits of server clustering

A clustered environment helps you manage hardware, applications, and website failures, ensuring uptime and availability. By saving engineering efforts, it can drastically reduce costs associated with system recovery and help your business grow in the long run via the following benefits:

Flexibility and scalability

An individual server handles everything from the network connection to storage for a business. By deploying a multi-server architecture with clustering capabilities, you can significantly improve the flexibility and scalability of that server.

In other words, clustering lets you scale one server to handle the increasing resource demand. Not to mention, it’s simpler for businesses to deploy an additional node to an existing cluster. If you have dedicated server hosting, you can do so with a simple phone call.

Improved availability and performance

A cluster with a dedicated database server can improve website or application speed by offloading database-related tasks onto a specialized server. This setup lets you improve performance while increasing support for simultaneous connections.

If you comply with regulations such as PCI DSS (Payment Card Industry Data Security Standards), server clusters become a practical necessity. This is especially relevant if you store financial information on a server that doesn’t connect to the Internet.

Reduced IT costs

Companies need a network with built-in redundancy to ensure customers can always connect. Besides that, the servers need to act as a single system. A clustered environment helps prevent downtime and lower costs by keeping the server fully operational. As clustered servers work together on a single network, they reduce risk vulnerability while boosting network performance.

Customizable infrastructure

Clustered server architecture can benefit businesses of all sizes as it allows them to customize the number of servers and the hardware it runs on. This can include anything from virtualization to server GPU. Using custom-built infrastructure ensures your environment is engineered for your workload and allows for process optimization and cost management while eliminating single points of failure. While determining the most cost-effective architecture for your needs may be a complex task, a reputable service provider can help you with exactly that.

The true cost of downtime

Are cluster server systems really that beneficial? How costly can downtime truly be to your business? Well, take Facebook’s network outage in October 2021, which lasted six hours. This resulted in an estimated revenue loss of $99.75 million before users could get back online. That’s a loss of over $16 million per hour.

Now, most businesses won’t lose as much revenue as Facebook, however, rising hourly downtime costs persist and require serious consideration. According to Uptime Institute’s 2024 Outage Analysis Report, 54% of the survey respondents reported that their most recent severe outage resulted in total financial losses of $100,000 or more. An unlucky 16% of respondents reported outage costs upward of $1 million. However, besides financial losses, businesses reported facing reputational damage and compliance breaches.

If your business requires reliable IT services, consider server clusters. They are a critical investment for long-term growth and performance. A clustered environment will boost performance and ensure infrastructure availability, scalability, and reliability.

Power your infrastructure with Liquid Web cluster hosting

Server clustering is a powerful strategy for businesses seeking scalable and reliable IT infrastructure. However, implementing and managing a cluster environment requires expertise, resources, and cutting-edge technology. This is where Liquid Web shines, offering comprehensive cluster hosting solutions designed to meet the most demanding business requirements to ensure:

• Unparalleled system reliability
• Seamless scalability
• High-performance infrastructure
• Expert management and 24/7 support
• Customizable cluster configurations
• Security-first approach

Whether you’re running complex web applications, resource-intensive databases, or mission-critical enterprise systems, Liquid Web’s cluster hosting ensures your infrastructure remains operational, efficient, and responsive. If you need expert support, contact Liquid Web today.

Related Resources

Multi-Server Architecture: Is it Right for You?

Server Cluster Benefits: Deliver Maximum Performance

Server Clusters and High Availability: An Overview

Network Security vs Cybersecurity: Differences and Similarities

What Is High Performance Cloud Computing?