How to backup your data

26 Apr 2024

I'll be writing a few posts about datahoarding in the future, so what better way to start off than by talking about backups?

The most commonly referred to phrase is: 3-2-1 backup.

What is 3-2-1 backup?

3-2-1 backup is a best practice for backup and recovery, but also a quite easy to remember phrase. Each of the numbers are a part of a sentence as shown here.

• Keep at least 3 copies of your data
• Keep the backed-up data on 2 different storage types
• Keep at least 1 copy of the data offsite

Keep at least 3 copies of your data

In addition to your original data, you should keep 2 backups.

Keep the backed-up data on 2 different storage types

The chances of having 2 failures on the same storage type are much greater than having 2 failures on 2 different storage types. If you have data on an internal drive, make sure you have a secondary storage type, such as an external or removable storage.

Keep at least 1 copy of the data offsite

Even if you have 2 copies on 2 separate storage types stored onsite, a local disaster could wipe out both of them. Keep a third copy in an offsite location, like the cloud.

Implementing 3-2-1 backup in my own setup

I have an old computer that I have setup as a server on my local network. It serves media files, runs my self-hosted YouTube, a dashboard for my home and some other stuff. The computer is equipped with 2 12TB drives that are mirrored with ZFS. This means I have my first 2 copies of the data (original data + 1 backup).

To get my 3rd backup I have a 3rd 12TB drive connected to a Raspberry Pi. The Raspberry Pi is located in a garden shed, but still connected to the local network. Through the local network it periodically SSHs into my server and downloads all the files to its drive. This is done with SCP, which I have written a bit about here: SCP.

With the Raspberry Pi I have achieved 3 copies of my data, and 2 different storage types. However my garden shed can hardly be called “offsite”, so that part is still missing. Therefore I have acquired a 4th 12TB drive that I routinely swap out with the 3rd one in the garden shed. The surplus harddrive is then stored with a trusted family member at an actual offsite location.

Please backup your data before it is too late. The best time to start was years ago, the second best is now.