Backups vs. Redundancy: What’s the Difference?

Backups and redundancy schemes are both data protection methods, but they are not interchangeable. Join us as we explore what makes them different, and why that’s important to you.

Redundancy is a data protection method intended as a real-time fail-safe measure against hard drive failure. A common redundancy feature found in servers and NAS boxes to prevent data loss is RAID (which stands for Redundant Array of Independent Disks), which creates multiple copies of files across several hard drives. If one hard drive in the array fails, the other hard drives pick up the slack with (usually) no interruption. A backup, on the other hand, doesn’t provide real-time protection, but it does provide protection against a greater set of problems, including failed drives, device theft, fire, or even just accidentally deleting files.

What Redundancy Is Actually For

In a nutshell, redundant data storage provides a real-time fail-safe against hard drive failure rather than an actual backup of your data. The idea is that the other hard drives in the array can immediately kick in and save the day without any downtime. This type of redundancy is typically used on servers or NAS boxes where the downtime of recovering from a failed hard drive is not an option.

RELATED: How to Use Multiple Disks Intelligently: An Introduction to RAID

And that right there is really the main purpose of redundant storage: reliability and uptime. If a hard drive fails and there’s no data redundancy in place, it can temporarily take out all of the data until the failed hard drive can get replaced and a backup can be restored.

Redundancy isn’t as important for regular consumers like you and me, but it’s critical for businesses that rely on data storage. This is especially true for companies that offer cloud storage or file hosting—any kind of downtime is bad for business.

Backups Protect Against All Types of Data Loss

There are a lot of ways you can lose data: accidental deletion, file corruption, drive failure, malware, software bugs, theft, damage, and more. Redundancy only protects against drive failure, whereas a true backup protects against every one of these factors (or at least most of them).

RELATED: What’s the Best Way to Back Up My Computer?

Let’s take accidental file deletion as an example. If you accidentally delete a file, redundancy won’t save you, since the redundant copy of the file in the RAID setup also gets deleted.

The backup, though, would have that accidentally-deleted file still intact on a completely separate, independent storage medium. This is why you should always back up even your NAS, even if it’s already set up for RAID.

RELATED: How to Create a Local Backup of Your Synology NAS

How You Should Back Up Your Data

If you regularly back up all the files on your computer to a separate hard drive and call it a day, that’s great, but it’s only a start. The truth is, you may not be doing as good of a job as you could be when it comes to backing up your data.

RELATED: What’s the Difference Between Cloud File Syncing and Cloud Backup?

Ideally, you want to have both a local backup of your data and a backup stored at an offsite location. The local backup is there to keep you protected against things like accidental file deletion and hard drive failure. Having an immediately accessible backup means restoring is that much faster.

But, what if your computer and your local backup drive are stolen? What if your home is hit by natural disaster? That offsite backup means that after you replace your computer, you can still restore all your data. Having that second copy of your backup also means you’re better protected in case one of those backups fails.

On top of having multiple backups, it’s important that you store them not only in completely separate locations, but that you store them in safe locations. For example, you could store one in a safe deposit box at your local bank and the second one in your own safe at home. Or you could even have one of your backup methods be to the cloud, which instantly takes care of the separate and safe location.

RELATED: What’s the Best Online Backup Service?

In the end, if all you do is plug in an external hard drive and sync files to it whenever you remember to do so, that’s better than nothing. Hell, if they’re not super important files or anything, then sure, what’s the problem, right? But you likely have some data on your computer that you’d be devastated over if you completely lost it. So do yourself a favor and do your backup due diligence!

Craig Lloyd writes about smarthome for How-To Geek, and is an aspiring handyman who loves tinkering with anything and everything around the house. He's also a mediocre gamer, aviation geek, baseball fan, motorcyclist, and proud introvert.