Navigating High Availability, Fault Tolerance, and Disaster Recovery Strategies

Disaster Recovery Plan

Businesses need IT infrastructure to store data and build applications that keep the business running. The infrastructure includes a network, data platform, computing, workplace, and edge capabilities. Conventional infrastructure like hardware, servers, and data centers are configured, maintained, and managed manually. 

In keeping IT infrastructure running around the clock, companies use three main strategies — these are fault tolerance, high availability, and disaster recovery.  Although these strategies are useful in ensuring that businesses run uninterrupted, they work differently. Each strategy has a varying methodology and addresses a unique problem. 

In this article, we expound on each strategy separately and take a look at fault tolerance vs high availability and disaster recovery vs. high availability. 

High Availability 

In very basic terms, high availability may be defined as the ability of a system to run and remain accessible for a defined period of time without downtime. Expressed as a percentage, it can give you an indication of how often you can expect system downtime due to shutdown or scheduled maintenance. 

It’s impractical to expect a system to have a rate of 100% in a year. Downtimes of about 5 to 6 minutes in a year are considered accessible. This means a 99.99% operational uptime. For many organizations, this uptime is still unreasonable. It may be lower than this depending on the company, available resources, and industry. 

How High Availability Works 

In organizational systems, high availability works by eliminating single points of failure through failover and redundancy components. This concept involves ensuring that failure in one component does not cause the entire system to become unavailable. 

Clustering technologies are used to design in virtualized environments. This means that if one of the virtual machines collapses, an alternative machine in the network takes over. This keeps the system running without interruptions. 

Having redundant components within the system boosts availability. But this is not the only way to maintain system uptime. Others are automatic redirection of workloads and early detection of system failures. 

Application of High Availability Strategies

The architecture of high-availability strategies can handle significant workloads that require high uptime. In situations where system or application failure can spell doom for an organization or business, it can be used to reduce downtimes. 

Even with less than 6 minutes of downtime each year, the strategies can cause businesses to lose thousands of dollars. It could also result in productivity loss, damaged reputation, and impact service delivery negatively. 

By fixing failures in a timely and automatic manner, systems prevent this from happening. 

Fun Fact:
From 2018-2020, there were 50 disaster events that totaled $237.2 billion in damage in the U.S. alone.

Fault Tolerance 

This IT infrastructure strategy involves keeping the system working without experiencing downtime following the failure of one or multiple components. Fault-tolerant systems feature two coupled components to provide redundancy. The components are very similar. If the main component ceases to operate, the other takes over. 

How Fault Tolerance Works

Just like high availability, fault tolerance systems use redundancy to maintain uptime. Redundancy is achieved by running a single operation on multiple servers simultaneously. This ensures one server takes over immediately after the primary server fails. 

Fault-tolerant systems achieve redundancy by keeping and running identical copies of virtual machines in different hosts. Inputs and changes in the main virtual machine are duplicated in the secondary machine. This allows for instant workload transfers to duplicate virtual machines if the main machine is corrupted

Application of Fault Tolerance Strategies 

You should go for this strategy if you’re looking for a zero-downtime solution. This IT infrastructure strategy comes in handy in supporting mission-critical projects like running apps where other systems can suffer irreversible loss should they experience a few seconds of downtime. 

Fault Tolerance vs High Availability Comparison

It requires a higher investment compared to the strategy. However, the two IT infrastructure structure systems differ in the sense that it is more strict than high availability. Though both focus on downtime, the latter delivers minimal downtime while the former delivers zero downtime.

In 2021 there were 20 disaster events that totaled over $1 billion in damages.

Disaster Recovery 

This IT infrastructure strategy is focused on responding to incidents that impact your system and the quick recovery of system functionalities.  It includes a plan, team, solutions, and recovery sites. The metrics that businesses use to monitor disaster recovery are recovery time and recovery point objectives. 

Application of Disaster Recovery

These strategies enable businesses to bounce back following a disruptive incident that causes serious downtimes and affects production sites. Such incidents can include power outages, software failure, cyberattacks, or human error. 

These incidents can occur unexpectedly, they are mostly impossible to detect or avoid. Businesses that are looking to enhance their preparedness can use this IT strategy. 

How the Disaster Recovery Strategy Works 

Disaster recovery involves storing notable workloads and data in a separate location. Businesses have to invest in a good solution to shift workloads and data to remote locations. The solution takes over operations when the main system fails.

A Disaster Recovery vs. High Availability Comparison

Unlike fault tolerance and high availability, disaster recovery is focused on helping businesses deal with disruptive occurrences that cause the entire IT infrastructure to fail. This strategy is tech-centric and data-centric. 

Its main aim is to restore data and get IT infrastructure components back in operation as fast as possible. The recovery varies from high availability and fault tolerance in terms of focus. Both of them seek to minimize system downtimes, whereas it is focused on restoring data after a business suffers a loss.

Final Thoughts 

Businesses use three main strategies to keep their IT infrastructure system running around the clock. These strategies are high availability, fault tolerance, and disaster recovery.  

If you’re running mission-critical applications or handling sensitive data that businesses rely on to power their operations, keeping your IT infrastructure running around the clock is critical. 

Of equal importance is the ability to restore data following a disruptive event like a system failure, power outage, or cyberattack. All 3 strategies are the major participants that IT professionals use to manage IT infrastructure. 

Each of these strategies has unique use cases. Although high availability and fault tolerance use similar strategies to maximize system uptimes, they vary in intensity.  


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