Synology Backup to Another Synology: Full Guide

Yes, you can back up one Synology NAS to another Synology NAS, and Synology provides several built-in tools to do it. The most common method is using the built-in Hyper Backup app to push backups from the source NAS to a target NAS over your network or the internet. You can also use Snapshot Replication for block-level, near-instant snapshots, or rsync and Synology Drive ShareSync for more specific needs. This guide explains each method, how to set them up, and which one fits your situation.

Why Back Up a Synology to Another Synology?

Having a second Synology NAS is a common way to follow the 3-2-1 backup rule: keep three copies of your data, on two different types of media, with one copy offsite. A second NAS can be placed in a different room, a different building, or even a different city. This protects you against:

• Hardware failure of the primary NAS
• Accidental deletion or corruption of files
• Ransomware that encrypts your primary device
• Natural disasters like fire, flood, or theft

Because both devices are Synology, you get tight integration, easier management, and no licensing fees for the backup software.

Hyper Backup: The All-in-One Solution

Hyper Backup is Synology’s flagship backup tool. It supports backing up to a remote Synology NAS, as well as to external drives, cloud services, and rsync-compatible servers. It offers:

• Versioning: keep multiple historical versions of files
• Deduplication and compression to save space
• Scheduling and bandwidth control
• Encryption of backup data

To set it up:

1. Install Hyper Backup from the Package Center on the source NAS.
2. Open Hyper Backup and choose Data backup task.
3. Select Remote NAS device as the destination.
4. Enter the IP address or QuickConnect ID of the target NAS, along with credentials.
5. Choose a shared folder on the target for the backup.
6. Select folders and apps to back up.
7. Set a schedule and retention policy.

Hyper Backup creates a single backup file (with a .hbk extension) on the target. You can restore individual files or entire folders from the backup.

Snapshot Replication: Instant Point-in-Time Copies

If you need frequent, near-instant protection, Snapshot Replication is the way to go. It creates block-level snapshots of shared folders or LUNs, which are stored on the same NAS or replicated to a remote Synology. Snapshots are read-only copies that you can access instantly if files are deleted or corrupted.

Key features:

• Snapshots are created in seconds, regardless of data size
• Can be scheduled as often as every 5 minutes
• Replication sends only changed blocks to the target
• Snapshots are immediately accessible for recovery

To use it:

1. Install Snapshot Replication on both NAS devices.
2. On the source, create a snapshot schedule for the shared folder.
3. Enable Replication and add the target NAS as the remote destination.
4. Set the replication schedule (can be more frequent than the snapshot schedule).

Note: Snapshot Replication works best on Btrfs file system, which supports native snapshots. If your shared folder is on ext4, you can still use it but with some limitations.

Rsync: The Flexible Command-Line Option

For users who prefer a more hands-on approach, rsync is a standard Unix tool that Synology supports via the Remote Rsync package or built-in rsync service. It synchronizes files and directories between two locations, and it can be run manually or via cron jobs.

To set up rsync:

1. On the target NAS, enable rsync in Control Panel > File Services > rsync.
2. Create a backup user with rsync permissions.
3. On the source, use the command line (via SSH) or a tool like Hyper Backup that supports rsync as a destination.

Example command:

rsync -avz /volume1/source/ user@target:/volume1/backup/

Rsync is powerful but lacks built-in versioning and scheduling (unless you script it). It’s best for advanced users who need full control.

Synology Drive ShareSync: Real-Time Sync

If you need two-way synchronization between NAS devices (not just one-way backup), Synology Drive ShareSync is the tool. It syncs a shared folder between two Synology NAS units in real time. Changes made on either side are propagated to the other.

This is not a true backup (deletions are also synced), but it’s useful for collaboration or keeping two locations in sync. If you want a backup that preserves deleted files, use Hyper Backup or Snapshot Replication instead.

How to Choose the Right Method

Your choice depends on your priorities:

• Versioning and app backups: Hyper Backup is the most complete.
• Frequent, near-instant recovery: Snapshot Replication.
• Full control and scripting: rsync.
• Two-way sync: Synology Drive ShareSync.

Many users combine methods: use Snapshot Replication for frequent local protection and Hyper Backup for daily offsite backups.

Common Problems and Solutions

Here are typical issues and how to fix them:

• Connection fails: Check that the target NAS has a static IP or is reachable via QuickConnect. Firewall rules may block the port (usually 5000/5001 for DSM, 22 for rsync).
• Slow transfer: Enable compression in Hyper Backup, use a wired connection, and check network bandwidth.
• Insufficient space on target: Monitor storage usage and set retention policies to prune old versions.
• Permission errors: Ensure the backup user has write access to the target folder.

Costs and Alternatives

Backing up to a second Synology has no software cost, but you need to buy the hardware and cover electricity and maintenance. If you don’t have a second Synology, alternatives include:

• External USB drives (using Hyper Backup’s local backup)
• Cloud services like Synology C2, Amazon S3, or Backblaze B2
• Another NAS brand using rsync or SMB

Cloud backups add a monthly fee but offer offsite protection without a second device.

Frequently Asked Questions

Can I back up a Synology to another Synology over the internet?

Yes. You can use Hyper Backup with a remote NAS destination by entering the target’s IP address or QuickConnect ID. Ensure the target is accessible from the internet (via port forwarding or VPN) and that firewalls allow the connection.

Does Hyper Backup support backing up applications?

Yes, Hyper Backup can back up settings and data for supported Synology packages like Synology Drive, File Station, and others. You can select which apps to include in the backup task.

What is the difference between backup and synchronization?

Backup creates a copy of your data that is separate from the original, preserving versions and allowing recovery after deletion or corruption. Synchronization mirrors changes in real time, meaning deletions are also mirrored, so it does not protect against accidental deletion.

Can I use Snapshot Replication without Btrfs?

Yes, but with limitations. On ext4 file systems, Snapshot Replication uses a different mechanism (file-level) and may not support all features. It’s recommended to use Btrfs for full snapshot functionality.

How much storage do I need on the target NAS?

It depends on the size of your source data and the number of versions you keep. A good rule is to have at least 1.5 to 2 times the size of the source data to accommodate multiple versions and deduplication overhead.

Is it possible to restore from a backup if the target NAS fails?

Yes, as long as you have another copy or a backup of the backup. It’s best to have multiple backup destinations (e.g., a second NAS and a cloud service) to avoid a single point of failure.

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