SSH into the server
The first thing we have to do is to SSH into the server, because Duplicati will be running as a web service on port 8200 we need to forward connections to that port. Because I've already got Duplicati running on my desktop port 8200 is already taken so I'm going to be forwarding port 8000 on my desktop to port 8200 on the headless Linux server.
In PuTTY open go to Connections > SSH > Tunnels
Set the source port to
8000 and the destination to
localhost:8200 then hit Add
Or if your SSHing in from a Linux desktops then use
ssh example.com -L 8000:localhost:8200
Head over to the Duplicati download page and copy the link to the Debian installer (in Firefox you can right click > copy link location)
Then download the file on the server
Then run the installer using apt (not
sudo apt install ./duplicati_126.96.36.199-1_all.deb
If you don't already have Mono installed this will bring a lot of dependencies with it.
Finally enable and start the service
sudo systemctl enable duplicati.service sudo systemctl start duplicati.service
I found I needed to wait about 45 seconds for the service to start accepting connections.
Once Duplicati is installed open your web browser and go to http://localhost:8000
Click on Add Backup > Configure a new backup > Next
Give your backups a name, you don't need to use encryption but I'd highly recommend it, and I'd also recommend using their password generator and saving the password in a password manager.
Pick B2 Cloud Storage, put in your Bucket Name, a folder path, your account ID and your application key (from the instructions on setting up Backblaze). It's also a good idea to test your connection before continuing.
Select your source data
Setup a schedule that works for you, the default on of once a day is pretty reasonable for most personal backups.
Unless you have a reason to change them I'd leave the default options.
And your done, you can hit Run now to start the backups or just wait for the schedule to kick in.
It's that easy.