Redundant Systems: Definition, Important, Working Method



To those in the computer science field, redundant systems are a lifeline that protects our data and keeps everything running as it should. But why are system redundancies so significant, and what kind of redundant systems are there?

Well, that’s where we come in. This article will explain what redundant systems are, how they work, why they’re important, what would happen without them, and how they benefit the AV industry.

What does redundancy mean?

Nope, it's not that kind of redundancy. Redundancies in engineering terms just mean a kind of doubling or even triplication of specific components to enhance the reliability of a system. In layman’s terms, they act as disaster control.

Redundancy refers to any system in the background that serves to kick in when there's a problem or put in preventative measures to stop a problem in its tracks. They are extremely useful systems that provide users with lots of peace of mind and potentially save them a pretty penny in repairs.

Redundant Systems

What is the function of redundancy in systems?

System redundancy acts as a sort of fail-safe in the event of a problem or system breakdown. They essentially duplicate the vital parts of the system so that the whole system can function to an extent whilst the primary system is being repaired or replaced. As you might imagine, redundant systems are a critical lifeline in places where safety is vital, like hospitals or aircrafts.

System redundancies increase the reliability of a piece of machinery or IT system, so users know that in the event of system failure, the redundant system is working in the background to either mirror the primary function or start to kick in after an error has occurred.

Redundant systems do this at different speeds, with some taking immediate effect after a system failure and some taking a while to reboot.

Redundancies can also implement error detection and corrective measures to help warn the user of impending system breakdown. This is more common in IT scenarios but is helpful in all industries nonetheless.

Typically, there are two primary functions of redundancy: passive and active.

Passive redundancy kicks in after a component in a machine or system break down to buy the user some time and decrease any devastating impacts.

A festive example of passive redundancy would be placing an extra piece of tape on your Christmas presents to stop the wrapping from coming apart if any original tape falls off. Essentially, this system is only handy in the event of a failure. Without failure, it is basically just there for peace of mind.

Active redundancy is a little different. Active redundancy ensures that the probability of system failure is lower by implementing preventative measures. An example of this would be a regular error or virus detection in your computer. This redundant system continually works in the background to spot any problems before they cause a major issue.

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What could happen without system redundancy?

Life without system redundancies wouldn’t be a disaster per se, but things definitely wouldn’t get done as fast.

You see, passive and active redundancies are in operation around us at all times. Your GPS system is an example of an active redundancy system, so if you get lost, your GPS already has a route home.

Another example might be a backup generator in a hospital, where life-saving equipment is kept on and functioning during power outages or natural disasters.

Hospital

Life would be a lot more complicated for those of us in the AV industry too. Redundant systems aren’t just automated robots; they’re also the everyday preventative measures we put in place, like buying extra-long cables when we don’t need it immediately but just in case, we decide to sit 10ft from the power outlet. System redundancies are vital for keeping visual displays functioning, keeping the software running, and data backed up in the event of a technical fault.

Data is a huge problem that we would face in the absence of redundant systems. Without routine automated backup, cold, warm or hot standby or virus protection, users may see large swathes of data lost after a power outage or system fault.

How do redundant systems work? Are there any disadvantages?

How redundant systems work is dictated primarily by the usage requirements. As there are so many different kinds of redundant systems that each have their individual roles, how they work can differ entirely from each other.

Redundant systems can only kick in when there is a system fault, which significantly impacts the latency. Or, they may be constantly running in the background, allowing for a quicker start-up period.

Ultimately, the function of these systems depends on whether they are software, hardware, information or time redundancy systems.

In terms of disadvantages, there are some very minor setbacks that you may want to consider before deploying lots of redundant systems.

Let’s start with the obvious.

More chance for complex error

Whether you’re working with physical equipment or complicated software, deploying lots of fail-safes leaves more opportunity for error. The more systems you introduce for one task, the more chances that one of those systems decides to stop working.

Now, with the right equipment and contingency measures, this doesn’t have to be a total disaster but it is something to consider when you’re thinking about damage control.

Reduced responsibility

Secondly, if you’re relying on automated contingency methods, you may start to find that responsibility amongst your staff starts to fade. The more redundant systems you put in place, the less you have to rely on handy repair workers that have years of experience and know what the error is just by looking at it.

We know that these people are invaluable, and when your contingency system fails, you may want them around to do its job.

Safety

Finally, you may have to consider the safety element. Although this is most prominent in engineering industries, it's still super important. If a system is running on its own with little error, it may be tempting to ignore it for a while and let it do its job, but this can cause you to overlook vital safety measures, resulting in system failure.

Types of redundant systems

In a broader sense, there are four different kinds of redundancy, they are:

  • Hardware
  • Information
  • Time
  • Software

Hardware redundancy

Component duplication as a fail-safe in the event of a fault is a prime example of hardware redundancy. The hardware redundancy works parallel to the primary system, so in the event of a system failure, it can easily pick up where it left off.

Information redundancy

Spotting errors and correcting are the primary functions of information redundancy. They ensure that data is transferred reliably across platforms and is continually backed up to prevent losing all our data in the event of a system breakdown.

Time redundancy

Time redundancies repeat a process more than once and assess the results to spot any errors, which helps to increase reliability over time.

Software redundancy

Software redundancies run the same task in a different software than the primary programme. This ensures that in the event of a fault with the primary software, the redundant software can pick it back up pretty quickly.

Software redundancy

These four general redundancies represent countless preventative and fail-safe measures that are individual to different industries. For example, the aviation industry may use multiple hydraulic systems to ensure that planes continue to function in the event of an error.

Whereas a video editor may use more comprehensive standby methods to increase their latency speed and preserve all their data in a power outage.

The beauty of these redundancies is that they are entirely customisable to your needs!

How important is redundancy in the AV industry?

All of us in the AV industry know how frustrating it is when you’re in the middle of a screening or editing process and everything just cuts out and you lose the last half an hour’s worth of work. Well, redundant systems are super useful for avoiding this very scenario.

Users may wish to employ standby systems to quickly get back to where they were in the event of system failure. We actually mentioned them a minute ago; they’re called cold, warm and hot standby. Don’t be fooled by their seemingly strange names.

These redundant systems could mean the difference between getting your data back quickly, or scrambling for hours re-doing your work from the last backup. Let’s go through them:

Cold standby: Cold standby is a typical low-cost redundancy option that functions in the event of a system error. If your system suddenly cuts out, your cold standby system attempts to bring you back to where you were, but substantially slower than other options.

This is because cold standby only functions when there is an error, so getting your data back might be a little trickier.

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Warm standby: Warm standby is a more improved redundancy and is constantly working in the background of your system, sending data back and forth. So, if there is a system fault, your warm standby speeds up the latency and brings you back to the last system backup.

Hot standby: Hot standby is the best option for those of us who want to be back to where we were in our work, to the letter. Hot standby is constantly running and mirrors the exact task of the primary system. So, in the event of an error, the system quickly comes back to life and all your work is safe and secure.

This is important for the AV industry because it streamlines production time, boosts engagement, optimizes your display usage and secures all of your hard work. You can use these redundancies for virtually any AV project, from video walls to editing.

And there you have it! Now you know all about redundant systems and how to use them to your advantage. For more handy AV advice, make sure you check out DEXON’s blog for more ways of optimizing your AV experience.

Reference list

D, Sagan, S. (2004). Learning from natural accidents. [online] Available at: https://web.archive.org/web/20040714202943/http://iis-db.stanford.edu/pubs/20276/sagan_oe_dec03.pdf.

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