There are three different types of backing up data. They are full backups, differential backups, and incremental backups. We will primarily be focusing on differential backups, analyzing their benefits, and how to properly utilize them.
How Do Differential Backups Work?
To understand how differential backups work, we need to start off with regular, full backups for context. A full backup copies all of your files, and puts them into a data repository. Every time you subsequently then create a new full backup, you copy a different instance and save it in the repository. Differential backups improve this system to optimize it even further. To create a differential backup, you need to first create a full, regular backup which you will use as a baseline. This is why it’s called “Differential”. It calculates the difference between your full backup and your current state which you wish to save, and then only saves the changed files, rather than all of them. So in other words, every time you create a differential backup, all of your files are still protected since any change that could cause an imbalance in your system, will be within that differential.
What Are the Benefits of Using Differential Backups?
The traditional full backup can be slow to create, take up a lot of space, and slow to use for recovery. This is simply because of the volume of the data that it needs to process. Differential backups improve on all of these issues. The backups themselves are created much more quickly since they don’t have to go through anywhere as much data, they take up less space, and are generally quicker to recover with. Here’s an example, let’s say you need to create daily backups. With the regular system, every day you will have to create a snapshot and save it separately. This way the size of your accumulated backups starts to build gradually, and this can especially be an issue for cloud-hosted backups in terms of cost efficiency. With differential backups, you only need the initial full backup and every subsequent differential backup will be only a fraction of the size. Then if you have to repeat that every day, it will only categorize the changes relative to the initial, full backup.
What Are the Downsides of Using Differential Backups?
The biggest issue with using differential backups is the linear increase of the time and space it requires with every cycle. Every time it goes through a cycle, it grows larger, since more files are likely to change the longer the system keeps going. For example, let’s say that on the first day, you create a full backup. On day two you create your first differential backup. On day three you create your second differential backup. The backup that you create on day three will have to copy the data from day two and day three, rather than only day three. This is how the system scales up over time. The way to resolve this issue is to simply create a new full backup and start the cycle anew. You can automate this to create a full backup to act as the new baseline after a certain threshold, minimizing the issue. Furthermore, if any of the backups during the chain happen to fail or backup incompletely for any reason, there is a chance that recovery will not be possible in this scenario. It is also more complex to recover from as well, in comparison to the traditional full backups.
Are There Any Ways to Mitigate the Downsides?
We have already discussed how to minimize the data bloat that occurs over time. However, we still need to tackle the other two big issues. Let’s tackle the file restoration first. The way differential backups restore files works is as follows. You first restore your configuration to the initial full backup that you have created, and then you implement the differential backup of your choice on top of it. If the initial full backup is compromised, then there is unlikely nothing to be done to remedy the situation. However, if the differential backup is affected, you may be able to get around it by using a previous or a later version, without losing too many of the files. The issue of the recovery being more complex ties into this as well. In essence, it isn’t that difficult to restore, but on a technological level, it creates an opportunity for failure since it is technically an extra additional step that has the potential to fail. By this metric, it is in essence, more difficult than a simple full backup.
What Are the Differences Between Differential and Incremental Backups?
Most usually confuse and mistake the two terms. We’ve explained how differential backups work, and in essence, incremental backups are similar, without the gradual data inflation. It only accounts for data changes since the previous backup in general, not just full backup. For example, let’s say you create a full backup on day one. You create an incremental backup on day two, and it copies all of the changed files relative to day one. When you create an incremental backup on day three, it will only copy file changes relative to day two. There is a downside, however, and that is in the recovery process. If the need for recovery ever does come up, you will have to go through the entire chain backward, without the ability to skip. Meaning if you have ten links in a chain, you will potentially have to go back all ten steps.
Using the Right Tool for Differential Backup
One of the key decisions is to select the right tool that offers comprehensive differential backup to suit your organization’s needs. ManageEngine AD360 is a converged identity platform that automatically backs up your AD environments and Microsoft 365 data. It also generates audit reports and log files that can help track what data was backed up. It can help with meeting the requirements of different compliance standards as well. Try this tool with a 30-day free trial.
Summary
Depending on what kind of system you need to create backups for, one of these three types will work best for you, knowing which one to opt for can be difficult at times. It is a fine balancing act between managing resources and opportunity costs when it comes to protecting your data this way. Hopefully, we’ve helped you gain some new insight into the matter.