What is Fault Tolerance? Definition, Requirements, and Examples [Everything You Need to Know]

Productivity and working environments require constant technical support, meaning that backup and server capacity must be in place to ensure that operations are never interrupted. That is where fault-tolerant technology comes in, to guard against power failures or hardware issues.

But, what is fault tolerance? How does it work, and what are some examples? In this article, you'll find a basic definition of fault tolerance. Then, we'll explore some key requirements and use cases for it in any workplace today. So, let's get started.

What is fault tolerance?

Fault tolerance is the design of a system that can continue to operate in the presence of errors or failures. It ensures that a system remains up and running without interruption. The term “fault tolerance” applies to both hardware and software.

In some cases, fault tolerance refers to a computer program's ability to detect and correct errors that might cause it to crash. For example, if a computer has a faulty device, it will issue an error message alerting the relevant user or technician to the problem.

Still, the elements of a workable approach include the following:

• It is usually a backup device taking over from a failed one;
• it is software stepping in to keep a program running;
• it is a system backup in case of data loss or system crash.

These are some of the key definitions of fault tolerance. Simply put, it's a safety measure that ensures work or operations can proceed seamlessly in the event of hardware or software failures.

Fault Tolerance Requirements

The need for fault tolerance is clear, though it may depend on the size of an organization and the amount of data or hardware it has to manage. Suppose we have a computer within an organization.

If it has about 100 gigabytes of data, it needs 150 to 200 gigabytes of storage. But if that storage fails, you need another disk with the same amount of data and storage capacity to replace it. So, in summary, a fault-tolerant system has three main requirements:

• Hardware fault-tolerant system
• Software fault-tolerant system
• Power fault-tolerant system or FTPS

A hardware system is typically a replaceable or portable hardware device that stands in for another person's device. As noted earlier, if a hard drive fails, another one in the computer or NAS device can take its place.

Another example of hardware fault tolerance is a backup server. If one server fails or is shut down, an identical server takes over its functions, so that productivity is not affected.

A fault-tolerant system is one that is created by using redundant processes. An example is a server-based database, in which data are updated frequently. Thus, if a failure occurs, the update or the most recent data can be retrieved.

Finally, power-failure-fault-tolerant systems include uninterruptible power supplies, so that equipment has backup batteries or a standby generator in case of a blackout.

3. Fault-Tolerant Examples

As described here, fault tolerance relies on having redundant hardware or software with identical specifications. That way, when one fails, the other can take over the workflow seamlessly. Thus, all three examples involve:

Backup/Server: Two identical servers running simultaneously. So, if one shuts down or fails, the other can seamlessly take over its duties. Redundant/Hot-Spare Hardware: Two or more pieces of hardware running in a device or network. If one fails, another piece manually or automatically replaces it. An example is having two identical hard drives in a computer. If one fails, the other takes over. Software: This is more about self-repair rather than replacement. So, if software detects an issue, it will restart itself after saving information (like a driver or design tool).

These are all examples of fault-tolerant systems in today's world, which can be adapted and updated according to an organization's needs. What does not change is the principle of a backup system standing ready to take over from the primary one.

Conclusions

These are some of the key aspects of fault tolerance, which can vary from one organization to another but is beneficial to all sizes of business, mainly because it ensures that productivity or workflow does not have to come to a halt or be interrupted.