What is Backup and restore in Computer systems and its types?

Backup and restore! We hear tech enthusiasts uttering these terms quite often. Well, even we ourselves know this term quite well. Backup is something which most of us are acquainted with. It is about storing a set of files or save the current state of a system to a safe place. While restoring is just the opposite. It is about getting access to that saved state to implement it in our systems to make things work like before. Well, it is the definition of backup and restores, which most users will give most often. And yes, that’s pretty simple for non-techy guys

But just like advancement in other spheres of technology, the process of backup can even be divided into numerous types depending upon how exactly those backups are taken. For the most efficient backup solution, and to waste the minimum bandwidth there are a number of backup strategies which are implemented by different backup software companies and data scientists. So here I will discuss what is backup and restore, and the different backup techniques, which you should know about. It can be helpful for finding the most appropriate backup solution for your business or your personal needs.

What is the Full backup?

A full backup is the simplest strategy of backup, where the complete set of files in a particular location or physical storage is backed up to a physically different location typically a cloud storage. Backup can also be taken to an external hard drive or anywhere else or anywhere else depending upon the resources you have.

Taking a full backup is a judicious decision when you are planning to switch to a new system or want to do a complete reset of the system, which you have access to. For example a mobile phone or a computer. But taking a full backup regularly is a waste of time and space as taking a full backup is a time-taking process, and a regular full backup also consumes a lot of space.

What is a Differential backup?

It is a different strategy of backup which can be implemented only after a full back up. In the differential backup, the changes after the full backup will be added to the backup, which eventually consumes fewer resources and is not time taking. Let me explain differential backup with an example.

Differential backup

Let me consider you have taken the complete backup of your system of Sunday. On Monday, you will only have to take the backup of the files, which were added on Monday, and on Tuesday, you will have to back up the things which were created on Monday and Tuesday. It goes on unless you eventually restore the files from the backup.

Thus, only those things will be backed up with differential back, which were created after the full backup of the system was made.

What is the Incremental backup?

Incremental backup is yet another strategy of backup, pretty similar to differential backup, but is not completely same. It is pretty similar to differential backup, but the regular backup from the system will be stored in different chunks. Let me explain with an example.

Incremental backup

Let’s consider you have taken a full system backup on Sunday. On Monday, the backup that will be taken will only have the things which were added to that on Monday. While on Tuesday, only those things will be backed up, which were added on Tuesday and so on.

Thus, with the incremental backup, the size of the regular backups get reduced as it contains only the additional data, which were created on that particular day. But the only con with incremental backup is that, if one chunk in the middle gets corrupted, the backup elements after that chunk will be of no use.

What is a Synthetic backup?

Synthetic backup is a combination of full backup and incremental or differential backup. In this process, the incremental or differential backup pieces will be appended to the full backup at regular intervals.

Actually, the name of this backup is Synthetic because it not back up the data from original source instead of that it takes full backup from the previous full back up archives and then integrates it to the incremental backup to add latest data in to it. 

Generally, it uses in the situation where the admin has time shortage or the system configuration not allow to take backup from the original source. It is pretty fast in nature.

For example, a full backup was taken on Sunday from the pre-existing backup archives. Then after that, the incremental or differential backups will be taken on the next days from Monday to Saturday or so on. Eventually, on the last day, all the backup chunks will be added to the full backup. This will continue either every week or month or at regular intervals.

What is the Reverse incremental backup?

This reverse incremental backup technique implements the flexibility of incremental backup technique on a full backup. Here the data which are changed regularly are added to the previous full backup, and this process is repeated regularly.

For example, you have taken a backup on Sunday. On Monday they changes made will be added to the full backup, and on Tuesday the changes will be appended to the full backup, which already contain the data backed up on Monday. Thus, at the time of restoring, you just need to restore the last backup chunk. It will contain all the data, which was previously present on your system.


Restore or restoration is the process of getting the backup image and store it to the old location, to start working again at the point, when the backup was taken. Depending upon where the data was backed up, the restoration process can take place either from a cloud location or from a physical location like an external hard drive or SSD.

Depending upon the type of backup, which was used, the restoration process should take place accordingly for the best performance and for getting the most appropriate recovery.

In case of a single sized full backup, the backup copy is needed for the restoration process. While if an incremental backup was taken, the full backup should be first obtained, and then the additional chunks should be added to it in tandem for the restoration to be complete. While in reverse incremental backup, the only chunk, which comprises the full backup needs to be obtained to start the restoration process.

Summing up the things

So let me finalize. Full backup is all about taking the complete backup of a system. It should be taken once or after really large intervals of time, in case you need to take it more than once. Taking regular full backups squeezes your bandwidth, and takes up a lot of space, which doesn’t make sense.

Differential backup is good, but the ultimate size of the differential backups too increase with time. It consume less bandwidth than a full backup, but more than the incremental backup, which makes it a good choice to switch to incremental backup if you have a choice.

Incremental backup is a good backup strategy where only the changes are backed up. It eventually squeezes less bandwidth and a very short time is required for taking an incremental backup. The only con is, the backup will become unrecoverable once a single chunk from the middle is lost.

To solve the problem of incremental backup, reverse incremental backup is implemented. It is the best backup strategy, but the server has to do some extra work appending the regular backups to the full sized backup.

Synthetic backups are pretty good for restoration as most part of the backup will be available in a single full backup chunk. The server has to do some extra work at the set intervals, to add the extra chunks to the backup file.

But you should also be able to take your decision judiciously about the backup strategy depending upon how much data needs to be backed up regularly, and whether your backup provider allows a certain strategy of backup. Incremental backup is even good when a large amount of data is backed up regularly, or else for a small number of data changes, a differential backup is a good solution.

Thus, incremental or reverse incremental backup followed by a full backup is the best option. Hope the information was helpful for you. Have questions? Feel free to comment it down below.