rsync backup

This example covers how to backup (manually or automatically) the userdata partition of your Batocera machine to a NAS. This allows you to recover your data to a previous state in case of data loss.

The following tutorial is based on a Synology NAS which is running on Synology's DSM version 6.x or later.

1. Enable the following services on the Synology NAS via the Synology DSM web GUI as follows:
   • Under SMB, navigate to Control Panel → File Services → SMB and check “Enable SMB service”.
     
   • Under SSH, navigate to Control Panel → Terminal & SNMP and check “Enable SSH service”. Then, for Port set the value 22.
     
   • Under rsync, navigate to Control Panel → File Services → rsync and check “Enable rsync service”. Then, for SSH encryption port set the value 22.
     

     You don't have to worry that port 22 is used by SSH and rsync at the same time. This is a common setup and the functionality of each service will not be interfered/disrupted in any way!

2. A user (without administrative privileges) will need to be created on the Synology NAS. For this example the user will be named backup.
3. Create a shared folder where the Batocera backup data can be stored to. For this example, the folder will be named batoceraBackup. Enable the read/write data permission for the user backup on the user permissions page:
   
4. Create a firewall rule on the Synology NAS so that the Batocera machine can send its data over the network to the Synology NAS. The rule must allow the following two services:
   • Windows file server
   • Encrypted terminal service (includes encrypted rsync and SFTP)

In addition it is also strongly recommended to limit the firewall rule to allow only the static IP address of the Batocera system (that's why it is important to set a static IP for the Batocera system):

Now SSH into your Batocera system and execute the following command to create a custom scripts folder:

mkdir -p /userdata/scripts

Now create the following script file:

nano /userdata/scripts/romsBackup.sh

And paste the following content (replace <your_password> with the according backup user its user password and <Synology_NAS_IP_address/hostname> with the static IP address/hostname of your Synology NAS):

#!/bin/sh
USER=backup
PASS=<your_password>
SHARE=//<Synology_NAS_IP_address/hostname>/batoceraBackup
MOUNT_POINT=/tmp/tempMountFolder
mkdir -p "$MOUNT_POINT"
mount -t cifs -o username="$USER",password="$PASS" "$SHARE" "$MOUNT_POINT"
rsync -Pav --delete -e ssh /userdata/roms "$MOUNT_POINT"
cd /tmp
umount -f "$MOUNT_POINT"
exit 0

Save the file and quit the editor.

Now create the following script file:

nano /userdata/scripts/userdataBackup.sh

And paste the following content (replace <your_password> with the according backup user its user password and <Synology_NAS_IP_address/hostname> with the static IP address/hostname of your Synology NAS):

#!/bin/sh
USER=backup
PASS=<your_password>
SHARE=//<Synology_NAS_IP_address/hostname>/batoceraBackup
MOUNT_POINT=/tmp/tempMountFolder
mkdir -p "$MOUNT_POINT"
mount -t cifs -o username="$USER",password="$PASS" "$SHARE" "$MOUNT_POINT"
cd "$MOUNT_POINT"
tar cfv "$MOUNT_POINT"/batoceraBackup.tar /userdata --exclude=roms --exclude=saves
rm -rf ./batoceraBackup.tar
cd /tmp
umount -f "$MOUNT_POINT"
exit 0

Save the file and quit the editor.

Now create the following script file:

nano /userdata/scripts/systemBackup.sh

And paste the following content:

#!/bin/sh
/userdata/scripts/romsBackup.sh
/userdata/scripts/userdataBackup.sh
batocera-es-swissknife --emukill && shutdown -h now

Save the file and quit the editor.

Now make all three scripts executable by executing:

chmod +x /userdata/scripts/*.sh

You can test your scripts by executing them as follows:

Backup userdata:

/userdata/scripts/userdataBackup.sh

Backup games:

/userdata/scripts/romsBackup.sh

Backup userdata and games:

/userdata/scripts/systemBackup.sh

If you are planning to only backup your data manually by executing your scripts manually, you can stop here.

Now let's set up the optional automation part for automatic backups of your userdata and your games:

SSH with user root into your Synology NAS (Unfortunately you have to use a Synology user which is part of the administrators group, otherwise SSH access will be declined. To avoid any permission issues, we will user root here.). Then execute the following commands (replace <Batocera_IP_address/hostname> with the static IP address of your Batocera system) for passwordless login by using SSH secure authentication key from your Synology NAS to your Batocera system (if you have already created an SSH key for your root user in the past on your Synology NAS, skip the first command!):

ssh-keygen

Confirm everything without inserting anything and by just hitting the [Enter] key on your keyboard!

Now execute the following command:

cat ~/.ssh/id_rsa.pub | ssh root@<Batocera_IP_address/hostname> 'cat >> /userdata/system/.ssh/authorized_keys'

Insert the Batocera root user's password (Default password: linux).
Now test the passwordless SSH login from your Synology NAS to your Batocera system.

If passwordless SSH login from your Synology NAS to your Batocera system works, you can now go back to the Synology DSM web GUI and create the according automation task as follows: Navigate to Control Panel → Task Scheduler → Create → Scheduled Task → User-defined script → General: For Task insert a custom task name (e.g. batoceraBackup) and for user choose root → Schedule: Configure a desired custom schedule → Task Settings: For User-defined script insert the following (Replace <Batocera_MAC_address> with the according MAC address of your Batocera system, <Synology_network_interface> with the according network interface name through which you want to send the magic packet to (the one which is within the same Layer 2 subnet as your Batocera system (e.g. eth0) and <Batocera_IP_address/hostname> with the static IP address/hostname of your Batocera system.):

#!/bin/sh
sudo synonet --wake <Batocera_MAC_address> <Synology_network_interface>
sleep 30
ssh root@<Batocera_IP_address/hostname> sh ../scripts/systemBackup.sh

Confirm by clicking on OK.

That's it! Your scheduled backup automation should work now.

You can test it by running the task manually via the Task Scheduler as follows:

Navigate to Control Panel → Task Scheduler → Look out for your specific task, highlight it and click on Run.