# Backing Up TrueNAS SCALE to Synology Using rsync

> Synology as a backup-only NAS

By Zsolt Bizderi · Published 2026-01-23
Canonical: https://ambientnode.uk/backing-up-truenas-scale-to-synology-using-rsync

I have been a long-time Synology user and still consider their hardware excellent. However, last year Synology made several controversial decisions that ultimately pushed me to build a TrueNAS SCALE server as my primary storage platform.

That said, I did not abandon Synology entirely. I kept two Synology NAS devices for backups of my TrueNAS server, one on-site and one off-site. This guide documents how to configure rsync on TrueNAS SCALE to back up data to a Synology NAS reliably and securely on-site. The same configuration applies to off-site sync; a [VPN](/wireguard-vpn/) should be used for transport security.

This guide uses a dedicated user named `rsync` for all three accounts involved: the Synology rsync account, the Synology local user account, and the TrueNAS SCALE user account.

---

## Synology Configuration

* Enable the rsync service:
  + Control Panel > File Services > rsync
  + Enable rsync service
  + Add rsync account
  + Click Edit rsync Account
  + Add the `rsync` user and set a strong password
* Create and configure the user:
  + Control Panel > User & Group > Create user `rsync`
  + Add the user to the administrators and users groups
  + Grant read/write access to:
    - `homes`
    - `NetBackup` (default rsync target directory created by Synology when rsync is enabled)
  + Grant permission to use the rsync application
* Enable SSH:
  + Control Panel > Terminal & SNMP
  + Enable SSH service

---

## TrueNAS SCALE Configuration

* Create the rsync user:
  + Credentials > Users > Add
  + Username: `rsync`
  + Enable: Shell access, SMB access, TrueNAS access (full admin)
  + Grant this user access to all datasets you intend to back up
* Create SSH credentials:
  + Credentials > Backup Credentials > SSH Connections
  + Create a new SSH connection
  + Generate a new key pair
  + Leave the remote key field empty
  + Save the connection
* Copy the public SSH key:
  + Credentials > SSH Keypairs
  + Open the newly created key
  + Copy the public key
* Configure SSH access on Synology:
  + SSH into the Synology NAS as the `rsync` user from another machine
  + Create the SSH directory:

```
mkdir -p /var/services/homes/rsync/.ssh
```

+ Create the authorized keys file and paste the public key into the file:

```
vim /var/services/homes/rsync/.ssh/authorized_keys
```

save it with :wq

* Set permissions:

```
chmod 700 /var/services/homes/rsync/.ssh
chmod 600 /var/services/homes/rsync/.ssh/authorized_keys
```

* Finalize SSH connection in TrueNAS:
  + Edit the previously created SSH connection
  + Click Discover Remote Host Key
  + Save

---

## Creating the rsync Task

* In TrueNas, go to Data Protection > Rsync Tasks > Add
* Configure the task:
  + Path: select the dataset to back up
  + User: rsync (alternatively, try root)
  + Direction: Push
  + Rsync Mode: SSH
  + Connect Using: SSH connection from keychain
  + SSH Connection: select the Synology connection
  + Remote Path: /volume1/NetBackup
  + Enable Validate Remote Path
* Optional: enable Delete if you want files deleted on TrueNAS to also be deleted on Synology

---

## Notes

The initial synchronization can take a long time depending on the amount of data. Subsequent runs are incremental and only transfer changed or new files, making ongoing backups fast and efficient.