We are already in the year 2021, and I believe that by this stage we already know how important backup is within an IT environment. Backup is one of the most important items in terms of data protection, since in the event of a disaster, such as a ransomware attack, or even a catastrophe, such as a fire in a data center, it is only backup that can guarantee the return of data to the IT production environment.
In order for the backup to be successfully restored, the solution and environment must first be designed to ensure that the location where the backup is being stored is safe, since a problem or situation similar to those mentioned above could occur.
When designing a backup solution and environment, there are several best practices to follow. The one I consider to be the safest these days is the 3-2-1 backup rule. This rule has a simple approach that helps us understand how many backup copies we should have and where we should store them.
The 3-2-1 rule became widespread in the IT market through a photographer called Peter Krogh. He said that there are two types of people: those who have already had a storage failure and those who are yet to have one. In other words, no matter how much you save your backup on storage, it doesn't mean that your data will be safe and sound forever. This storage may present some kind of problem or even be compromised the moment you suffer an attack.
The Rule
After understanding a little about why you should have the 3-2-1 rule implemented in your backup environment, let's now present it in a simple way:
The name 3-2-1 was given because of three factors: the amount of backup we should have, the amount of media we should store the backup on and the locations where the backup will be stored.
We therefore suggest
- Have at least 3 copies of your data;
- Store copies on at least 2 different types of media;
- Keep at least 1 of the copies somewhere outside your work environment.
Below is an illustration in which Veeam demonstrates in an article a very simple way of how the 3-2-1 rule works.
Now that we've understood a little and seen how this good backup practice works, we'll go into detail on each of its concepts.
Have at least 3 copies of your data backed up
The first rule of good 3-2-1 backup practice is to have three copies of your data, i.e. in addition to your original data in your production environment, you should also have two other copies.
The fact that you have a backup, however secure it may seem, does not guarantee the security of having this data available. Pay close attention to this part, as your backups must necessarily be in another place where the original data is. For example, if you have your personal files on one disk, you should back them up on another, physically separate disk.
This way, you can protect yourself against any physical failure, whether mechanical or logical, that the original data disk may have.
In addition, for the third copy of the data that you are going to make, this same argument must also be considered. This is precisely what the second rule of 3-2-1 backup, which I'm going to talk about now, addresses.
Store copies on at least 2 different types of media
The rule suggests having each of these copies on different media, in other words, we should store the two copies we have of our data on two different media. These media don't necessarily have to be different from each other, since as I mentioned above, we can have each copy on two different hard drives. In addition, we can also consider USB hard drives, pen-drives, DVDs and so on.
The most important thing at this point is that we have both copies of our data on different media from the original.
Keep at least 1 of the copies somewhere outside your work environment
Once you have different copies, stored on different media, you need to store one of these copies somewhere different too.
This means that we need to consider leaving one of the copies of the data in a place outside the work environment where the original data is located. This is what we usually call offsite. That's right, we need to have a copy outside the place where the data is produced.
This offsite location has several options you can adopt. If your company has a subsidiary, for example, you could leave the original data and one of the copies at the head office and one of the other two copies stored at the subsidiary. Another possibility would be to store one of the backups in a cloud. At AWS we have S3, which we can analogize to an external hard drive in the cloud. Finally, if the amount of data you have is very large, the use of tape stored in an external location may be viable.
Having presented the 3-2-1 backup rule here, you can see that it is very effective when it comes to data protection. What's more, this best practice is very widespread and used by Veeam, one of the largest manufacturers in the backup and data replication sector.
