What is high availability in IT and how does it affect SMEs?

After reading this article, you will better understand:

• What is high availability?
• Its advantage for SMEs
• How is it measured?
• Best practices for implementing it in your business

Available infrastructure: a productive organization

It's no secret that businesses are increasingly dependent on the vagaries of technology. Employee productivity is directly proportional to the availability of the company's IT services, hence the need to rely on a stable, but above all, available, IT infrastructure.

This is where the term high availability comes into play, which is a guarantee of the quality of the design of an organization's IT infrastructure.

High availability: definition

High availability is a characteristic of an IT system that guarantees a certain level of operational performance over a given period. It is a measure of the quality of the design of a company's IT infrastructure. The goal is to ensure that your IT systems are available at all times, or at least as much as possible.

High availability is measured as a percentage. For example, 99.9% availability means that your system is down for a maximum of 8.76 hours per year. This may seem like a lot, but it's actually quite good. For comparison, 99.99% availability means only 52.56 minutes of downtime per year.

How is high availability measured?

When discussing high availability, you will often hear about a number of "nines". Each additional nine sharply reduces the downtime allowed over a year:

• 99% (two nines): about 3.65 days of downtime per year
• 99.9% (three nines): about 8.76 hours per year
• 99.99% (four nines): about 52.56 minutes per year
• 99.999% (five nines): about 5.25 minutes per year

Each extra nine also demands more redundancy and therefore a larger investment. The right target depends on the system: your email and accounting software may not need the same level as an online ordering platform. When a provider promises a level of availability in an SLA, check how downtime is calculated and whether planned maintenance windows are excluded.

Why is high availability important for SMEs?

For SMEs, high availability is crucial because downtime can be extremely costly. Every minute your systems are down, you're losing money. Your employees can't work, your customers can't access your services, and your reputation suffers.

According to various studies, the average cost of IT downtime for SMEs can range from $10,000 to $50,000 per hour. For some businesses, it can be even higher. That's why investing in high availability is so important. Consider working with a managed IT service provider to ensure your systems remain available.

Best practices for implementing high availability

1. Implement redundancy

Redundancy is the key to high availability. This means having backup systems in place so that if one fails, another can take over. This can include redundant servers, storage systems, and network connections.

2. Use cloud services

Cloud services can help improve availability by providing redundant infrastructure and automatic failover. Many cloud providers offer SLAs (Service Level Agreements) that guarantee a certain level of availability.

3. Regular monitoring and maintenance

Regular monitoring helps you identify potential issues before they become problems. Implement monitoring tools that alert you to any issues in real-time. Additionally, regular maintenance ensures that your systems are running optimally. Learn about essential IT security practices to maintain system health.

4. Have a disaster recovery plan

Even with high availability measures in place, disasters can still happen. Having a disaster recovery plan ensures that you can quickly recover from any incident. Read our guide on IT succession planning for more information.

5. Distribute the load

Load balancing spreads traffic to your applications across several servers. If one server becomes overloaded or fails, the others continue to respond, and users often notice nothing.

6. Eliminate single points of failure

Look for any component whose failure would bring down the whole system: a single internet connection, one firewall, one storage array, or a server without a power supply backup. Storage redundancy such as RAID, a second internet link and an uninterruptible power supply are common ways to remove these weak links. For the most critical systems, hosting resources in more than one location also protects against power outages and local disasters.

7. Test your failover

A redundant system that has never been tested offers only theoretical protection. Schedule regular tests to confirm that failover works, that backups can actually be restored and that your team knows the procedure.

Common mistakes to avoid

• Treating backups as high availability. Backups protect your data, but restoring them takes time. High availability aims to keep services running.
• Aiming for the same level everywhere. Not every system deserves five nines. Concentrate investments on the systems your business truly cannot do without.
• Forgetting dependencies. A redundant server is of little use if it depends on a single network switch or a single cloud account configured without safeguards.
• Neglecting documentation. In a crisis, clear procedures save precious time.

Where should an SME start?

1. List your critical systems and the business processes that depend on them.
2. Define, for each system, how much downtime and data loss you could tolerate.
3. Identify the single points of failure in your current infrastructure.
4. Prioritize improvements according to business impact and budget.
5. Integrate high availability into your business continuity plan and review it regularly.

Nexxo can help you achieve high availability

At Nexxo, we specialize in helping SMEs implement high availability solutions. Contact us today to learn how we can help ensure your IT systems are always available when you need them.

Our managed IT services include continuous monitoring, maintenance and backup management, so your infrastructure stays available while your team focuses on its work.