Four Best Practices for Developing High Availability Applications

User experience is now at the forefront of most organizations’ software development strategies. Service outages or system failures that disrupt users can quickly damage brand reputation, leading companies to find high availability solutions that prevent downtime.

In a nutshell, high availability applications rely on redundant, backup components to ensure they run without interruption and avoid any single point of failure. When servers or hardware stop working or software updates crash the system, high availability ensures applications can still run normally for end-users, with no noticeable difference in service.

For companies that plan to scale up their applications for a wider audience, they need to build highly durable, high availability applications that can operate continuously. Here are some best practices that development teams should focus on during that process.

Stress Testing and Code Reviews

Poorly written code is one of the biggest causes of unplanned failures, especially during system updates or the addition of new features. Furthermore, bugs and bad code will often carry over into redundant systems, undermining the core benefits of high availability.

Testing is vital for preventing this—manual regression test session, automated unit testing, and end-to-end testing are a few ways to make sure applications are fully functional when any changes are made, and that infrastructure is robust enough to handle the new features.

Developers need to plan ahead when it comes to deploying changes but also allow space to test those changes in a live environment. Establish a means of traceability that allows developers to reproduce errors, as this will build a greater understanding of any bugs in the system or any loopholes that users can exploit.

Monitoring and Responding to Metrics

It is important to understand what usage patterns exist in high availability software, such as what time of day people use the software, how many people are using it, and how long they use it for, to name a few examples.

It’s the developer’s responsibility to implement monitoring tools and take action on the resulting metrics. With high availability software, these metrics help determine specific resource requirements to ensure top performance at peak times, as well as reducing costs off-peak. They can also inform organizations on any need to scale applications up or down

Failure detection is also key, as developers need the ability to respond to unplanned failures immediately. Bespoke dashboards are a great way to monitor issues and track metrics for high availability applications and their system infrastructure.

Keeping Users in The Loop

Aside from monitoring high availability software internally, it’s essential to communicate with users, listen to their feedback, and follow up with them on reported issues. Consider implementing tools and procedures that enable and enhance that back-and-forth contact.

Users expect customer service levels that match the “always-on” nature of high availability applications, so be sure to offer them an open channel of communication, preferably within the app itself. This feature will also help developers act more quickly to fix issues. Just be sure to notify users when those issues are rectified.

Preparing for Scalability

The process of scaling high availability applications requires a careful balance of performance, availability, maintenance and even expenditures. Before scaling anything, it’s important to recognize where to introduce or remove resources to maintain the application’s high availability.

When scaling performance, incremental updates allow changes to be tested with a small percentage of users, gradually increasing to the whole user base. Adding additional servers for more robust redundancy is another option if IT budgets can be scaled alongside business needs.

Closing Summary

For companies that cannot afford to lose revenue or suffer reputational damage, high availability software is a necessary investment to mitigate downtime. Ensuring high availability is a complicated process, so consider working with qualified software engineering partners that can guide your organization through the process.