Nowadays, it’s hard to imagine trying to pay at your favorite store, but their payment system isn’t working, or their mobile app is down. It’s really frustrating! In today’s digital world, when a website or app we use isn’t working, it can be incredibly frustrating and even put us in a bad mood. To avoid these moments or downtime in our applications, there’s something called High Availability.

Imagine this!: You have an ant colony. If one of the anthills is destroyed, the ants have backup routes (like creating a new one) to replace the one that was lost. Even within the colony, ants have specific roles and tasks—if one dies, another takes over its role.

That’s how a high availability system works: there’s always a Plan B (or C, or D).

What Is High Availability?

Simply put, High Availability refers to a system’s ability to operate continuously without interruptions—even if an incident occurs, the system keeps running.

Why High Availability Matters

In the digital age, you need to offer 24/7 service to be productive and appealing to customers. Providing reliability builds customer trust, reduces frustration, and increases revenue. It also helps prevent crises in critical services, giving your business more security.

Types of High Availability

Luckily for us (and our wallets), there are different types of high availability:

• Active-Passive: In this model, the secondary system remains inactive or offline and only kicks in when the primary system fails. This usually requires manual intervention or extra configuration to switch over.
• Active-Active: In this setup, multiple systems work simultaneously and share the workload. If one fails, the others automatically take over. This solution offers better performance and scalability.

How High Availability Works

It might sound a bit complex, but the main idea is to have multiple backups and copies of each system component.

• Redundancy: Having exact copies of critical system components, which is easier when the system is fully decoupled.
• Failover: If a component fails or stops working, another one automatically takes over as much as possible.
• Load Balancing: It’s essential to distribute traffic or usage across different identical components.

How Digital Leaders Ensure 24/7 Availability

• Netflix, AWS, Azure, and GCP: They use multiple data centers (AWS regions) so that if one fails, the service remains active.
• Banks and Fintechs: They implement database replicas to avoid outages affecting transactions.
• Social Media Platforms: They implement global redundancy across multiple regions to stay online all the time.

In short, High Availability is the unsung hero working tirelessly so everything runs smoothly and we can enjoy our favorite services without interruption. For businesses, it’s key to happy customers. For users, it’s the guarantee that the digital world is always one click away.

Want to learn how to implement it in your company? Let’s talk.

Article written by: Engineer Eduardo Herrera.