Install Syncthing

What Syncthing is

Syncthing keeps folders identical on several computers. If someone puts a file in the company folder, it shows up on the others, without passing through any cloud service along the way. The computers talk directly to each other, and the content is encrypted during transport. The program is free and open source.

The difference from a cloud service is where the files are stored. Here they are on your own computers, all of them, all the time. That means you can reach them without internet, that no service can close the account in the middle of a trade fair week, and that there is no storage limit other than the hard drive. It also means that it only works when at least two of your computers are running at the same time.

Installing on Windows

The project itself delivers a zip file with the program, without an installation guide and without an icon in the taskbar. It works, but it feels unfamiliar. On the download page syncthing.net/downloads, the project therefore lists two add-ons that make the Windows version normal to use: Syncthing Windows Setup, which is a real installation file, and SyncTrayzor, which puts the program in the system tray at the bottom right and starts it with the computer. The original project is now archived, so look for the further developed fork (same name, new maintainer) that Syncthing itself links to.

Take one of them if you are not used to the terminal. Both are maintained by people other than Syncthing's own developers, which is stated openly on the download page, and both fetch the same Syncthing underneath.

Installing on Linux Mint

Use the project's own package repository, so Syncthing is updated along with the rest of the system. Open a terminal with Ctrl plus Alt plus T and run the lines in order:

sudo mkdir -p /etc/apt/keyrings
sudo curl -L -o /etc/apt/keyrings/syncthing-archive-keyring.gpg https://syncthing.net/release-key.gpg
echo "deb [signed-by=/etc/apt/keyrings/syncthing-archive-keyring.gpg] https://apt.syncthing.net/ syncthing stable-v2" | sudo tee /etc/apt/sources.list.d/syncthing.list
sudo apt-get update
sudo apt-get install syncthing

The lines come from the project's own documentation. Then start the program from the menu. If you want it to start automatically the next time you log in, without opening it by hand, run systemctl --user enable --now syncthing.service in Terminal. The interface is a web page that opens at the address 127.0.0.1:8384 in the browser, and that address can only be reached by the computer Syncthing runs on. That is on purpose.

Three things to do first

1. Pair two computers. Each installation has a long ID shown under Actions and Show ID. Add the other computer's ID as a device, approve the request that appears on the other side, and wait until both show as connected.
2. Share a folder, but only one to start with. Create an empty folder named after the company, share it with the other device and add a test file. If you see the file on the other computer within a minute, everything works.
3. Turn on file versioning in the folder settings. Choose simple versioning and keep five versions. It takes a few megabytes and saves you the day someone saves over the quote.

The most common trap

Believing that this is a backup. It is not, and the difference only shows when something goes wrong. Syncthing mirrors. If someone deletes a file, it is deleted everywhere, and the same thing happens if a folder is corrupted or if a virus encrypts it. The mirroring does its job and spreads the damage to every connected computer in under a minute.

Hence the versioning in point three, which gives you something to restore from. Also take a real copy of the most important things at regular intervals, on a USB drive or in a cloud service that you do not sync against. On Windows there is another trap: when the computer connects to a new network, Windows sets it as public, and then the direct connections are blocked. Change the network to private on the new network, otherwise you will wonder why the sync suddenly takes half an hour.