# My backup container

Snapshot a [BTRFS](https://docs.kernel.org/filesystems/btrfs.html) volume from a [Docker container](https://www.docker.com/) and robustly back it up to multiple [BorgBackup](https://borgbackup.readthedocs.io/en/stable/index.html) repositories on a schedule.

## Quick start

- Check out [docker-compose.yml](docker-compose.yml) and set the environment variables according to your needs
- Update the password in the [.env](.env) file

## Background

I've been using this setup for the past years and have managed to avoid disaster by restoring all my data. This is all thanks to the excellent backup tool called Borg. The scripts in the this repository serve as an opinionated thin wrapper around it. The Docker image I provide in this repository is generic enough to be used verbatim in many self-hosting setups. However, it's just a thin wrapper and a set of configs that work together well. It's been a long journey for me to find the backup setup that works for me, so I make this available to save others from pitfalls and serve as a potenrial starting point for your own backup container.

## Features

- Back up the snapshot of a BTRFS volume to avoid files changing during backup
  > I self-host multiple databases and this is the most feasible way of avoiding data corruption
- Schedule the backup so that it keeps running automatically
- Keep a weekly rotated log of all previous runs
- Back up the same source to multiple borg repositories

### Multi-target backups

In case we don't have disk-level redundancy and would still wish to follow the [3-2-1 rule](https://en.wikipedia.org/wiki/Backup), we have to back up the same source folder to multiple targets. For instance, I don't have a RAID setup but instead back up an SSD into rsync.net and a local HDD at the same time.

You can see in the [docker-compose.yml](docker-compose.yml) file that we can set `BORG_REPO_0`, `BORG_REPO_1`, `BORG_PASSPHRASE_0`, `BORG_PASSPHRASE_1`, etc.

The backup script first takes `BORG_REPO_0` and the corresponding env vars and sets up the [`BORG_REPO`](https://borgbackup.readthedocs.io/en/stable/usage/general.html#repository-urls), `BORG_REMOTE_PATH`, and `BORG_PASSPHRASE` environment variables for borg. Once that finished (successfully or otherwise), the script checks whether `BORG_REPO_1` exists, if so, it sets `BORG_REPO` and the other env vars to their expected values and backs up again. The script keeps going to `BORG_REPO_2`, `BORG_REPO_3` and so on as long as these are set. Otherwise, it unsets the previous `BORG_REPO` and corresponding env vars and goes to sleep.

Thus, the following sets of environment variables are valid for multi-target backups:

- ```sh
    - BORG_PASSPHRASE=$PASSWORD
    - BORG_REPO=/local-backup
  ```

  > This just backs up to a local repository

- ```sh
    - BORG_PASSPHRASE_0=$PASSWORD
    - BORG_REPO_0=/local-backup
  ```

  > This just backs up to a local repository

- ```sh
    - BORG_PASSPHRASE_0=$PASSWORD
    - BORG_REPO_0=/local-backup

    - BORG_PASSPHRASE_1=$PASSWORD2
    - BORG_REPO_1=/local-backup2
  ```

  > This backs up to two different local repositories

- ```sh
    - BORG_PASSPHRASE_0=$PASSWORD
    - BORG_REMOTE_PATH_0=borg1
    - BORG_REPO_0=my-username@my-username.rsync.net:~/backup

    - BORG_PASSPHRASE_1=$PASSWORD
    - BORG_REPO_1=/local-backup
  ```

  > This first back up to a remote repository, then to a local one

## Repository layout

- src
  - backup.sh: Creates a Borg repository if it doesn't exist, snapshots the BTRFS volume, backs up, and removes old backups
  - backup-wrapper.sh: Runs backup.sh for every Borg repository provided through environment variables
  - schedule.sh: Persists the logs of backup-wrapper.sh and runs it in a while True.

## Related resources

- I like this video on how to install Debian with BTRFS https://www.youtube.com/watch?v=MoWApyUb5w8. Of course, a btrfs disk can be created after installation as well.
- rsync.net has a special discount when using borgbackup: https://www.rsync.net/products/borg.html
- Checking out the documentation of BorgBackup is worth it: https://www.borgbackup.org/demo.html