Modern businesses cannot operate effectively without IT, and their operations hinge on high availability. However, this dependence on technology also presents a major challenge: what to do in the event of a breakdown?
Many small and medium-sized businesses look for an infrastructure that can withstand (almost) anything, hoping this will keep their operations up and running. This article from our Montreal managed IT services experts details how to guarantee the high availability of your enterprise’s IT infrastructure. Let’s jump in.
Definition of high IT availability
High availability refers to the ability of a system to remain accessible, operational, functional and responsive, even when a failure occurs. This implies a high level of fault tolerance, minimal downtime, and an architecture designed to absorb shocks without compromising usage.
This is not an abstract concept. It’s an architectural strategy, supported by technical components such as redundant servers, load balancers, distributed storage, proactive supervision and automated failover. It has a single objective: to ensure that critical applications remain available without interruption.
How important is high availability?
Given that outages can directly translate to lost contracts, invoicing gridlock, or data loss, high availability isn’t optional; it’s a fundamental need. An SME that sells, produces, manages or collaborates via digital tools or business software cannot tolerate an unplanned outage.
High availability protects against direct losses: aborted sales, corrupted data, suspended services. Outages don’t just cause immediate problems; they also negatively affect the perception of reliability, slow down internal response times, and impede operational efficiency. So, high availability also helps build and maintain the trust that customers, partners, and employees have in an organization.
Most SMEs can’t afford to have a team on standby to restart a server or restore access to a database. The system has to stand on its own, which is precisely what a high-availability infrastructure delivers.
How does a high-availability infrastructure work?
A high-availability infrastructure isn’t built on a single solution; it requires a combination of interconnected mechanisms working together to create true resilience.
1. Load balancing: for reliable hosting
A company looking to enhance the availability of its IT infrastructure can start by implementing load balancing across its web servers. This simple operation allows tasks or communications within a network to be distributed over two or more separate servers to improve performance.
Load balancing keeps a company’s IT services accessible, even under heavy demand, by evenly distributing workloads across several servers via a load balancer, i.e. a device that intelligently sorts user requests according to the space available on the servers.
In addition, load balancing prevents services from becoming unavailable in the event of a breakdown. It will detect a server failure and redirect users to another server, which will receive requests until the initial server is up and running again.
Load balancing also makes it possible for an application to be updated on one server, rather than all of them. An SME can therefore test an update on a specific sample of users with minimal risk to their IT system.
2. Hardware redundancy: performance, capacity and reliability
Hardware redundancy offers another critical layer of support for maintaining high availability.
Roughly speaking, it consists in the duplicate installation of hardware and equipment that enables the immediate and complete resumption of IT activities in the event of a breakdown, accident or IT disaster.
Not only does redundancy provide access to a back-up solution in the event of computer failure or data loss, it also optimizes system capacity and performance. Redundant components function together to improve overall performance and availability, much like a team whose collaborative efforts lead to faster and more efficient problem solving.
How to measure high availability
To measure high availability, you measure the availability over a given period. The formula expresses the percentage of time a system remains accessible without interruption:
Availability (%) = [(Total time – Downtime) / Total time] x 100
For example, a service that operates 364 days out of 365 achieves around 99.73% availability. For mission-critical environments, we often aim for the famous “five nines”: 99.999%, or around 5 minutes of downtime per year.
These figures need to be analyzed pragmatically. Aiming for 100% availability is expensive, and not realistic for all companies. The goal is not to achieve perfection, but to find the right balance between the level of service required and the level of protection in place.
High availability and disaster recovery
A high-availability architecture limits interruptions. But it’s no substitute for an IT disaster recovery plan, which sets out what needs to be done in the event of a major incident like a widespread breakdown, cyber-attack, fire, or case of human error.
A recovery plan defines the roles, deadlines, procedures and tools to be mobilized to get back up and running quickly. It often relies on the same mechanisms as high availability: redundancy, backups, and monitoring. But it adds an organizational dimension. It anticipates chaos to better manage it.
A well-prepared SME combines both approaches: high availability to stay online, and disaster recovery to get back up and running if anything goes wrong.
How do you achieve high availability?
High availability can’t be achieved with a single tool or decision. It’s a question of both engineering and IT strategy, and involves combining several layers of protection to create a resilient whole. Here are the concrete steps required:
- Identify critical services: target what you cannot tolerate to fail, such as sales systems or customer databases.
- Implement redundancy: double up on servers, network connections and power supplies. There should be no single point of failure.
- Automate failover: in the event of a system failure, another system must automatically take over. This rapid failover avoids any visible interruption for the user.
- Implement continuous supervision: monitor performance and anomalies in real time so systems can react before interruption.
- Do regular testing: simulate failures, check restorations and validate recovery plans.
- Surround yourself with solid partners: outsource management to experts to guarantee a constant, secure level of service.
Ensuring high availability of your IT infrastructure
Load balancing and hardware redundancy work in tandem to provide high availability for IT infrastructure. Additional strategies can be implemented for even greater robustness. Preventive IT audits can also help protect your IT system-infrastructure. We may delve into these in greater detail in an upcoming piece. To be continued…
In the meantime, if you’d like to set up a reliable, high-performance IT infrastructure, feel free to contact us. Our team will be happy to provide the necessary assistance.
