Computer equipment is subject to failures that can bring great inconvenience and damage to companies. In this sense, high availability systems are essential for carrying out activities that rely on energy, location, operation, software, and hardware.

This technology ensures services are available 24/7 without interruptions or loss of information. For this reason, it is extremely important for large organizations, such as public agencies, critical infrastructure, and banks.

In this article, we dive deeper into the subject. Our text is divided into topics to make it easier for you to understand. These are:

• What is High Availability?

• What is a High Availability Cluster?

• How Important is High Availability to Organizations?

• Advantages of Infrastructure with High Availability Versus Infrastructure Without High Availability

• High Availability, Redundancy, and Fault Tolerance: What is the Difference?

• High Availability Products

• Important Points for the Implementation and Maintenance of High Availability Systems

Enjoy it!

• What is High Availability?

A high availability (HA) system consists of a technology that must be applied to the computer equipment of large companies and data centers in order to avoid the interruption of activities resulting from failures.

This is possible through an infrastructure designed for maximum uptime, known as 99.999 percent or the “five 9s”.

It works through the allocation of hardware and software, among other solutions, in a redundant way. In practice, this means they will work automatically if any of these items fail.

• What is a High Availability Cluster?

The word cluster (or clustering) is the same as “agglomeration”, as explained in this article. It is a term used in the most diverse contexts.

In the case of computing, it refers to a technology applied to two or more computers. We call these equipment nodes, and the number of nodes that can compose a cluster is unlimited.

A high availability cluster can be of two types: to be used in hardware and applications. In hardware high availability, we have a connection that makes it possible to change a component if there is an outage.     

In application high availability, the purpose is to ensure that applications work. As such, the cluster avoids long downtime when a system goes down. This model is useful with:

• Monitoring tools;
• Replication of systems and computers to replace equipment that may present problems; and
• Power generators.

In application high availability, a database is synchronized with the instances that make up the cluster, which divides operations among them, assuring that the system will continue to function normally even if an instance is stopped.

• How Important is High Availability to Organizations?

Regardless of the company’s industry, most of its departments need Internet access to function. A few examples are:

• Employees responsible for the sales sector use emails and social media to communicate with clients; 
• Those who lead the teams also use online means to communicate with their subordinates;
• The purchasing sector needs to be in constant contact with suppliers; and
• People who take care of marketing also access several platforms to carry out their activities.

We can conclude that high availability systems are of utmost importance to prevent loss of productivity related to time lost with IT disaster recovery.

Likewise, they preserve the credibility of the company, which is also critical, as damage to a brand’s reputation can be a major barrier to its growth. Key benefits of high availability include:

• Reduction of scheduled downtime;
• Guarantee of service continuity;
• High-level performance;
• Secure data.

• Advantages of Infrastructure with High Availability Versus Infrastructure Without High Availability

High availability hosting providers perform the same hosting services as traditional infrastructure. However, this is done in a way that eliminates the possibility of downtime by almost 100%. 

What must be taken into account is the cost of this downtime, which is often much higher than most people realize.

A company with affected infrastructure could have impacts on productivity, reduced to almost zero while that infrastructure is down, or still have an interruption that leads to bankruptcy.

That is because the loss of productivity is a secondary concern to the loss of reputation caused by downtime hassles. 

After all, clients prefer to hire the services of accessible and prepared organizations to serve them whenever they need it. In other words, investing in high availability hosting is of paramount importance to keep your company and brand available to your audience.

• High Availability, Redundancy, and Fault Tolerance: What is the Difference?

A system that features redundancy is not necessarily a high availability solution. For this, it needs to have means to detect failures, the possibility to perform high availability tests, and correct failures related to unavailable components.

Redundancy is hardware-based, while high availability strategies use software most of the time.

When it comes to the difference between high availability and fault tolerance, you should know that the latter requires complete redundancy in hardware. It is also essential to have hardware that identifies failures to ensure the entire system works together.

The advantage of this technology is the ability to retain memory and data for your programs. On the other hand, the adaptation to complex systems can take a little longer. Another problem is that the entire network can crash due to similar software failures presented by redundant systems.

Fault-tolerant systems are effective in preventing equipment problems, but in addition to being expensive, they do not prevent software failures, unlike high availability solutions.

• High Availability Products

If you have understood the importance of investing in high availability, we cover features that are critical to achieving the performance your business needs in this topic. Among the aspects that should be considered, we highlight:

• Hardware resilience;
• Environmental conditions;
• Data quality; and
• Durable software.

To have an efficient, high-availability system that addresses these points, it is essential to have resources such as servers, network interfaces, and hard drives that are resistant to problems such as power outages and hardware failures.

Also, you should strategically install multiple web application firewalls on your networks, which enable you to eliminate failures. Another extremely important resources are software stacks capable of resisting failures that may eventually occur.

• Important Points for the Implementation and Maintenance of High Availability Systems

High availability systems are adaptable to the needs of the organization hiring this service. Nevertheless, certain practices are widely indicated. Some of them are:

• Redundancy of systems and data through different machines;
• Deployment of applications on more than one server, in order to avoid machine overloads;
• Use of components to ensure maximum stability and availability;
• Spare resources for any failures;
• Tests capable of guaranteeing availability, performance, and security;
• Effective data backup and recovery strategies;
• Conducting tests that help prevent failures related to confidential information; and
• Use of 100% redundant router, load balancer, firewall, reverse proxy, and monitoring systems.

In this article, we discussed what high availability is and its importance to organizations, as well as the difference between redundancy and fault tolerance. We also pointed out aspects that are essential for the implementation of this technology.

If our text was helpful to you, please share it with others who might benefit from this knowledge. On our blog, you can find more content on high availability and information security, check it out. 

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