feat(docs): Template script for 3-2-1 backup of the assets and database (#6026)

* Added borg template cron job

* moved script to guides section

* Mentioned db backup location in docs

* Added directions for restoring backups

docs/docs/guides/template-backup-script.md

@@ -0,0 +1,82 @@
+# Backup Script
+
+[Borg](https://www.borgbackup.org/) is a feature-rich deduplicating archiving software with built-in versioning. We provide a template bash script that can be run daily/weekly as a [cron](https://wiki.archlinux.org/title/cron) job to back up your files and database. We encourage you to read the quick-start guide for Borg before running this script.
+
+This script assumes you have a second hard drive connected to your server for on-site backup and ssh access to a remote machine for your third off-site copy. [BorgBase](https://www.borgbase.com/) is an alternative option for off-site backups with a competitive pricing structure. You may choose to skip off-site backups entirely by removing the relevant lines from the template script.
+
+The database is saved to your Immich upload folder in the `database-backup` subdirectory. The database is then backed up and versioned with your assets by Borg. This ensures that the database backup is in sync with your assets in every snapshot.
+
+### Prerequisites
+
+- Borg needs to be installed on your server as well as the remote machine. You can find instructions to install Borg [here](https://borgbackup.readthedocs.io/en/latest/installation.html).
+- To run this sript as a non-root user, you should [add your username to the docker group](https://docs.docker.com/engine/install/linux-postinstall/).
+- To run this script non-interactively, set up [passwordless ssh](https://www.redhat.com/sysadmin/passwordless-ssh) to your remote machine from your server.
+
+To initialize the borg repository, run the following commands once.
+
+```bash title='Borg set-up'
+UPLOAD_LOCATION="/path/to/immich/directory"       # Immich database location, as set in your .env file
+BACKUP_PATH="/path/to/local/backup/directory"
+
+mkdir "$UPLOAD_LOCATION/database-backup"
+mkdir "$BACKUP_PATH/immich-borg"
+
+borg init --encryption=none "$BACKUP_PATH/immich-borg"
+
+## Remote set up
+REMOTE_HOST="remote_host@IP"
+REMOTE_BACKUP_PATH="/path/to/remote/backup/directory"
+
+ssh "$REMOTE_HOST" "mkdir $REMOTE_BACKUP_PATH/immich-borg"
+ssh "$REMOTE_HOST" "borg init --encryption=none $REMOTE_BACKUP_PATH/immich-borg"
+```
+
+Edit the following script as necessary and add it to your crontab. Note that this script assumes there are no spaces in your paths. If there are spaces, enclose the paths in double quotes.
+
+```bash title='Borg backup template'
+#!/bin/sh
+
+# Paths
+UPLOAD_LOCATION="/path/to/immich/directory"
+BACKUP_PATH="/path/to/local/backup/directory"
+REMOTE_HOST="remote_host@IP"
+REMOTE_BACKUP_PATH="/path/to/remote/backup/directory"
+
+
+### Local
+
+# Backup Immich database
+docker exec -t immich_postgres pg_dumpall -c -U postgres | /usr/bin/gzip > $UPLOAD_LOCATION/database-backup/immich-database.sql.gz
+
+### Append to local Borg repository
+borg create $BACKUP_PATH/immich-borg::{now} $UPLOAD_LOCATION --exclude $UPLOAD_LOCATION/thumbs/ --exclude $UPLOAD_LOCATION/encoded-video/
+borg prune --keep-weekly=4 --keep-monthly=3 $BACKUP_PATH/immich-borg
+borg compact $BACKUP_PATH/immich-borg
+
+
+### Append to remote Borg repository
+borg create $REMOTE_HOST:$REMOTE_BACKUP_PATH/immich-borg::{now} $UPLOAD_LOCATION --exclude $UPLOAD_LOCATION/thumbs/ --exclude $UPLOAD_LOCATION/encoded-video/
+borg prune --keep-weekly=4 --keep-monthly=3 $REMOTE_HOST:$REMOTE_BACKUP_PATH/immich-borg
+borg compact $REMOTE_HOST:$REMOTE_BACKUP_PATH/immich-borg
+```
+
+### Restoring
+
+To restore from a backup, use the `borg mount` command.
+
+```bash title='Restore from local backup'
+BACKUP_PATH="/path/to/local/backup/directory"
+mkdir /tmp/immich-mountpoint
+borg mount $BACKUP_PATH/immich-borg /tmp/immich-mountpoint
+cd /tmp/immich-mountpoint
+```
+
+```bash title='Restore from remote backup'
+REMOTE_HOST="remote_host@IP"
+REMOTE_BACKUP_PATH="/path/to/remote/backup/directory"
+mkdir /tmp/immich-mountpoint
+borg mount $REMOTE_HOST:$REMOTE_BACKUP_PATH/immich-borg /tmp/immich-mountpoint
+cd /tmp/immich-mountpoint
+```
+
+You can find available snapshots in seperate sub-directories at `/tmp/immich-mountpoint`. Restore the files you need, and unmount the Borg repository using `borg umount /tmp/immich-mountpoint`