How to back up your Synology NAS with Sync WebDAV

Sync WebDAV for Linux can be used with the built-in Hyper Backup app on a Synology NAS.

With this setup, the Sync WebDAV server runs directly on the Synology NAS. Hyper Backup connects to Sync WebDAV locally, while Sync WebDAV handles the connection to your Sync account and preserves end-to-end encryption.

You can use this configuration to:

• Back up your Synology NAS to Sync for an off-site cloud backup.
• Use Cloud Sync to copy your Sync files to your Synology NAS for a local copy of your Sync data.

Before you begin, you'll need:

• A Synology NAS with Hyper Backup installed.
• SSH access to the NAS.
• A Sync account with WebDAV Early Access enabled. Join the early access program.

Installing the Sync WebDAV server on the NAS

1. Enable SSH access on the NAS
   In DSM open Control Panel → Terminal & SNMP → Terminal, enable SSH service, and click Apply
2. SSH to the NAS
   From a computer on the same network as the NAS, open Terminal and connect to the NAS:
   ssh synology_username@nas_ip_address
   Your Synology account must be a member of the administrators group.
   (you can find your NAS IP address from DSM → Control Panel → Network → Network Interface)
3. Install and run Sync WebDAV on the NAS
   Follow these step-by-step instructions

The goal is to install Sync WebDAV directly on the NAS and run it in --headless mode. While testing, keep your Terminal window open. Once everything is working, run Sync WebDAV in --daemon mode so it continues running in the background and you can close Terminal and disable SSH.

Creating a Synology backup task

1. In DSM open Hyper Backup.
2. Click + → Data backup task.
3. Select WebDAV as the backup destination.
4. Enter:
   Server address: http://localhost:4918/
   Username: Your Sync email
   Password: Your Sync password
5. Choose the folders and applications on your Synology NAS that you want to back up.
6.  Configure your backup schedule and rotation policy.
7. Review the backup task and click Done.

Hyper Backup will now back up your selected NAS data to Sync through the locally running Sync WebDAV server.

Restoring a Synology backup

Hyper Backup stores NAS-to-remote backups in its own backup format. To restore them:

1. Make sure Sync WebDAV is running.
2. Open Hyper Backup.
3. Select the backup task.
4. Click Restore.
5. Select the files, folders, applications, or backup version you want to restore.

Backing up your Sync files to the Synology NAS

If you want a local copy of your Sync files on the NAS, use Cloud Sync instead of Hyper Backup.

1. Install and open Cloud Sync from DSM Package Center.
2.  Click + → WebDAV.
3. Enter:
   Server address: http://localhost:4918/
   Account: Your Sync email
   Password: Your Sync password
4. Select the local folder on your Synology NAS.
5. Select the folder in Sync you want to copy.
6. Set Sync direction to Download remote changes only.
7. Configure your schedule and other options.
8. Create the task.

Cloud Sync will periodically check Sync for changes and copy them to your NAS.

After restarting your NAS

If scheduled backups stop working after rebooting the NAS, make sure Sync WebDAV is running.

Troubleshooting

Synology cannot connect

Confirm Sync WebDAV is running and that the connection uses localhost, HTTP, and port 4918

sync-webdav: command not found

Reconnect your SSH session after installation.

If necessary: export PATH="$HOME/.sync-webdav/bin:$PATH"

Restart Sync WebDAV: sync-webdav --headless --daemon

Backups stopped after reboot

Make sure the Sync WebDAV server is running. Hyper Backup and Cloud Sync cannot connect to Sync unless the local WebDAV server is active.

Security notes

• Do not expose port 4918 to the Internet.
• Keep Sync WebDAV listening on localhost.
• Restrict SSH access to trusted devices and networks.
• Disable SSH when you no longer need it.
• Enable 2FA on your Sync account.
• Test restores before relying on the backup for critical data.