Incremental vs. Differential Backup: What's the Difference?

Zack Busch
Zack Busch  |  December 18, 2018

Finding the right backup software can be difficult. There’s a lot to digest when considering your backup options.

A good place to start, after deciding what you need to back up, is how often and to what extent you’ll need to back up your data.

It’s a more involved question than you might think. Professionally, companies probably back up servers way more often than personal computers. Transaction information and other key data gets backed up more often than text documents.

Knowing that, how often should that data be saved? Hourly? Daily? Weekly? And, if we’re ever in a situation where we need to recover our data, how would we want that data recovered?

A Full Backup

When we back up data, especially data that hasn’t been backed up before, we should always, always start with a full backup: Take all data on your drive(s) and save absolutely all of it.

The concept of a full backup is that you’re setting a baseline. You want a certain save point so that if your drives crash or your original data gets corrupted, your full backup is the bare minimum point where you could continue normal function. (See our discussion on hard drive cloning software for more about setting up that baseline.)

Beyond that baseline, where do you go? The most likely answer is that after setting your baseline backup, you’d like periodic backups on top of it for live data. In that case, you have a couple of choices.

Incremental vs. Differential Backups

Differential backups are backups that save all data that has changed since the last full backup. They can be scheduled to happen at any regularity but will always save anything and everything that differs from the last full backup.

Incremental backups differ slightly from differential backups in that they will save all data that has changed since the last backup of any kind. Full backup, partial backup, doesn’t matter. If the data is different than the last backup of any kind occurred, incremental backups kick in.

So what? Who cares about the last full backup versus the last backup of any kind?

It’s a fair question, and one that we can lay out the nuances of in detail.

Incremental vs. Differential Backups

 

Differential backups

Differential backups tend to be significantly larger than incremental ones. Differential backups save all changed data over a much larger range. As a result, you’ve got larger backups that will take more and more time as the backup size increases.

Because each differential backup takes the difference between current data and the last full backup, your differential backups will end up consuming significant storage space. To counteract this, consider making your full backups more regular.

Incremental backups

Incremental backups, on the other hand, tend to be smaller and build off each other. Because they back up to the last save of any kind, they tend to take less time and consume less drive space. While these backups build off each other and are quicker, they can come with risks as well.

Some incremental backup software will struggle if, when trying to restore from incremental backups, one of the increments has become corrupted. This leaves an incomplete piece in the restoration that can’t be recovered. So, incremental backups tend to need a little more care and may be more prone to file corruption risks.

Choosing a between the two

When deciding between these two backup types, you will want to verify your storage capacity. Incremental backups consume less overall storage, and while differential backups may feel more “complete” between full backups, they’ll also consume significantly more space than incremental ones. Take care to consider your infrastructure.

Your individual needs for the backup will also play a part in deciding between differential and incremental backups, and it will come down mainly to preference. Differential backups are great for backing up bulk information and can be run in off hours (e.g., overnight), negating the issue of long backup times. Incremental backups are great for quick burst backups that don’t disrupt productivity and might be incredibly useful for covering day-to-day tasks like document and media generation.

Don’t pit these backup types against each other, though; in fact, they can function extremely well in tandem. Consider, for example, a retailer or restaurant that performs numerous transactions hourly. This business could utilize incremental backups on an hourly basis, where transactions can be tracked at a constant rate and disruption to service would be fairly minimal.

Then, at the end of the day, a differential backup would take over and save the entire day’s worth of transactional data to a local or cloud server. The end result of this series of backups is continuously restorable data at both an hourly and daily level, establishing multiple levels of data integrity for the business.

Next steps in determining your backup type

In the technology age, backups are crucial to ensuring your business functions properly. For companies that rely heavily on servers carrying the day-to-day workload, consider exploring server backup software to make sure you’ll never have to worry about lost data. If cloud work is more your company’s speed, online backup software has your back, letting you worry more about your next undertaking. All these backup software types should offer incremental and differential options. Find what’s right for you and jump in.

Looking for a backup solution on a budget? Learn how these free backup software tools can help you avoid a data catastrophe in 2019.

Zack Busch
Author

Zack Busch

Zack is a Research Specialist who made the jump to the research realm after three years in IT support services. He studied mathematics, physics, and education at Truman State University. Zack enjoys video gaming, D&D, movies, TCGs, and spending time with his partner, dog, and two cats.