Per default cron sends the full result of each backup operation by email. If you want cron to only mail on error (non-zero exit code) you may want to use the following snippet. Pathes need to be modified according to your setup (this script is a user contribution).
This following script may be placed in `/etc/cron.daily/mailcow-backup` - do not forget to mark it as executable via `chmod +x`:
5 4 * * * cd /opt/mailcow-dockerized/; BACKUP_LOCATION=/external_share/backups/backup_script /opt/mailcow-dockerized/helper-scripts/backup_and_restore.sh backup mysql crypt redis --delete-days 3
# If you want to, use the acl util to backup permissions of some/all folders/files: getfacl -Rn /path
```
On the destination (in this case `/external_share/backups`) you may want to have snapshot capabilities (ZFS, Btrfs etc.). Snapshot daily and keep for n days for a consistent backup.
Do **not** rsync to a Samba share, you need to keep the correct permissions!
To restore you'd simply need to run rsync the other way round and restart Docker to re-read the volumes. Run `docker-compose pull` and `docker-compose up -d`.
If you are lucky Redis and MariaDB can automatically fix the inconsistent databases (if they _are_ inconsistent).
In case of a corrupted database you'd need to use the helper script to restore the inconsistent elements. If a restore fails, try to extract the backups and copy the files back manually. Keep the file permissions!