The term backup refers to the duplication of data from one storage medium to another. Backup, then, is nothing more than the saving of data (and thus the copying) in a secure medium: the answer as to its importance is quite obvious; in fact, backups allow us to recover data when it has been deleted by mistake, hardware damage, viruses or force majeure in a very simple and fast way since we have made a complete copy of the data ourselves, before the problem occurred.
Having a backup at hand is the quickest and cheapest solution to get everything back without wasting time. Let's think of a ransomware attack: if we have full and working backups, we are sure that we will have no problem restarting our business immediately.
This is what the 3-2-1 backup rule entails:
3: create one main backup and two copies of your data.
2: save your backups on two different types of media.
1: Keep at least one backup file offsite.
A 3-2-1 backup strategy reduces the impact of a single point of failure, such as a disk drive failure or a stolen device. For example, you can store a backup on an external hard drive, USB drive and cloud storage. If a disaster wipes out your on-site backups, your off-site cloud-based backup will come in handy!
There is no perfect backup system, but the 3-2-1 approach is a great start for most people and businesses. Even the US government recommends this approach!