pg_dumpall on a schedule, then restic to backup the dumps. I’m running Zalando Postgres in kubernetes so scheduled tasks and intercontainer networking is a bit simpler, but should be able to run a sidecar container in your compose file

+1 for long-ass backup script. First dump the databases with the appropriate command. Currently, I have only MariaDB and Postgres instances. Then, I use Borg to backup the database dumps and the docker volumes.

Database SQL dumps compress very well. I haven’t had any problems yet

I tried to find this on DDG but also had trouble so I dug it out of my docker compose

Use this docker container:

prodrigestivill/postgres-backup-local

(I have one of these for every docker compose stack/app)

It connects to your postgres and uses the pg_dump command on a schedule that you set with retention (choose how many to save)

The output then goes to whatever folder you want.

So have a main folder called docker data, this folder is backed up by borgmatic

Inside I have a folder per app, like authentik

In that I have folders like data, database, db-bak etc

Postgres data would be in Database and the output of the above dump would be in the db-bak folder.

So if I need to recover something, first step is to just copy the whole all folder and see if that works, if not I can grab a database dump and restore it into the database and see if that works. If not I can pull a db dump from any of my previous backups until I find one that works.

I don’t shutdown or stop the app container to backup the database.

In addition to hourly Borg backups for 24 hrs, I have zfs snapshots every 5 mins for an hour and the pgdump happens every hour as well. For a homelab this is probably more than sufficient

I setup borg around 4 months ago using option 1. I’ve messed around with it a bit, restoring a few backups, and haven’t run into any issues with corrupt/broken databases.

I just used the example script provided by borg, but modified it to include my docker data, and write info to a log file instead of the console.

Daily at midnight, a new backup of around 427gb of data is taken. At the moment that takes 2-15min to complete, depending on how much data has changed since yesterday; though the initial backup was closer to 45min. Then old backups are trimmed; Backups <24hr old are kept, along with 7 dailys, 3 weeklys, and 6 monthlys. Anything outside that scope gets deleted.

With the compression and de-duplication process borg does; the 15 backups I have so far (5.75tb of data) currently take up 255.74gb of space. 10/10 would recommend on that aspect alone.

/edit, one note: I’m not backing up Docker volumes directly, though you could just fine. Anything I want backed up lives in a regular folder that’s then bind mounted to a docker container. (including things like paperless-ngxs databases)

I just do the first option.

Everything is pretty much idle at 3am when the backups run, since it’s just me using the services. So I don’t really expect to have issues with DBs being backed up this way.

I mostly use postgres so I created myself a small docker image, which has the postgres client, restic and cron. It also gets a small bash script which executes pg_dump and then restic to backup the dump. pg_dump can be used while the database is used so no issues there. Restic stores the backup in a volume which points to an NFS share on my NAS. This script is called periodically by cron.

I use this image to start a backup-service alongside every database. So it’s part of the docker-compose.yml

I guess I’m a dummy, because I never even thought about this. Maybe I got lucky, but when I did restore from a backup, I didn’t have any issues. My containerized services came right back up like nothing was wrong. Though that may have been right before I successfully hosted my own (now defunct) Lemmy instance. I can’t remember, but I think I only had sqlite databases in my services at the time.

Snapshot with zfs, backup snapshot.

I guess the trouble is that you don’t want to read the volumes where the db files are because they’re not guaranteed to be consistent at a given point in time right?

Does the given engine support a backup method/utility that can be used to copy files to some volume on a set schedule?

With restic you can pipe to stdin, so I use mysqldump and pipe it to restic:

mysqldump --defaults-file=/root/backup_scripts/.my.cnf --databases db-name | restic backup --stdin --stdin-filename db-name.sql

The .my.cnf looks like this:

[mysqldump]
user=db-user
password="databasepassword"

I just started using some docker containers I found on Docker Hub designed for DB backups (e.g. prodrigestivill/postgres-backup-local) to automatically dump from the databases into a set folder, which is included in the restic backup. I know you could come up with scripts but this way, I could easily copy the compose code to other containers with different databases (and different passwords etc).

I have also been wanting to try borg for at least offsite backups. Currently been using a “long ass backup script” with how little time I currently have.

I use rsnapshot docker image from Linuxserver. The tool uses rsync incrementally and does rotation/ prunning for you (e.g. keep 10 days, 5 weeks, 8 months, 100 years). I just pointed it to the PostgreSQL data volume. This runs without interruption of service. To restore, I need to convert from WAL files into a dump… So, load an empty PostgreSQL container on any snapshot and run the dump command.

My plan to handle this is to switch my VMs to NixOS, set up NixOS with impermanence using a btrfs or zfs volume that gets backed up and wiped at every startup with another that holds persistent data that also gets backed up, and just reboot once per day.

I’m currently learning how to do impermanence in all the different ways, so this is a long goal, but Nix config + backups should handle everything.

Borgmatic is an automation tool for Borg. It has hooks for database backups.

https://torsion.org/borgmatic/docs/how-to/backup-your-databases/