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

In computing, the term high availability is used to define the period of time during which a service is available. It is also used to describe the time required for a system to respond to a user request.

High availability is therefore the attribute of a system or component that guarantees a high level of operational performance over a given period of time.

How is high availability measured?

When it comes to high availability, you'll always hear a number 9 mentioned. This is because it's measured by a certain system availability rate, in units of time, which usually starts at 99%.

This percentage translates to the length of time a system will be available, or unavailable. A system that is 99% available (2 new) means that the system will be unavailable 1% of the time, or 3.65 days a year, or 14 minutes per day (365 days × 1% = 3.65 days).

Because perfection is not considered possible, the industry standard for availability is five 9s, or 99.999%. This means that the system will be unavailable for only 5.25 minutes in a year, or 0.86 seconds per day. The table below shows the availability level based on the number of 9s.

How to achieve high availability?

Since this is an extremely broad topic and we could write an entire book on how an organization achieves high availability, we are providing you with a list of best practices that will assist you in achieving high availability.

TechTarget 's research center suggests eight factors to consider when achieving high availability:

• Eliminate single points of failure or any link that could impact the entire system if it became dysfunctional
• Ensure your systems and data are backed up and ready to be restored
• Use load balancing to distribute traffic to your applications and network across your servers or other hardware. A very popular distribution solution is HAProxy
• Continuously monitor the status of your backend servers
• Distribute your resources geographically to counter power outages or natural disasters
• Implement failover or distribution solutions: your data storage can be ensured by a RAID (Redundant Array of Independent Disks) or a SAN (Storage Area Network)
• Implement a system that detects failures as soon as they occur
• Choose hardware designed for high availability and test their operation before implementation

High availability and disaster recovery: never one without the other

You may be thinking that your disaster recovery plan is sufficient and that you don't need to implement high availability. The opposite is also often the case.

However, both are essential and will save you a lot of trouble in the event of a force majeure event, such as a cyberattack , for example.

In fact, your disaster recovery plan is part of your business continuity plan, which hopefully also includes high availability. All of these elements should be included in your IT master plan , a strategic tool of the utmost importance for managing your IT infrastructure.

Nexxo can help you implement high availability

You don't have a full-time IT employee and lack the resources to accomplish everything you'd like? You have an in-house team, but they're simply overwhelmed by the current workload?

Do not hesitate to contact us . We will evaluate together how we can assist you in the strategic management and technical support of your organization. We have been working for over 15 years with companies in various sectors and contribute to their growth with sound planning and management of their IT.