NAS server

Create snapshot of your Synology folders with Folder Sync (Part 3)

If you have two synology NASes  there are a lot of ways for you to backup your data.

You can backup your data using:

  1. File station : Drag and drop files between NASes
  2. Cloud Station ShareSync: One/Two way sync for files and folders that change frequently in real time (hot storage).
  3. Shared Folder Sync (this post): One way sync for files and folders that do not change that often (cold storage).
  4. Snapshot ReplicationSnapshots of your folders on specific periods of time.
  5. Hyper BackupData backed up are kept in a database which can be browsed, downloaded or restored with tailor-made multi-version explorer on DSM, Windows and Linux platforms.

In this post we will cover the Shared Folder Sync and in future posts, we will cover the rest of the backup/Replication features.

Shared Folder Sync

The Shared Folder Sync service allows users to sync shared folders from one Synology NAS device (the source) to other Synology NAS devices (the destination) in LAN or over the Internet.

Shared Folder Sync will perform a full sync of the selected shared folder(s) for the first time. Afterwards, only changed files will be synced. Files that have been removed from the source will also be removed from the destination.

This is how you enable it:

On NAS1:

On the destination Synology enable rsync services:

  1. Click on “Control panel”
  2. Click on “File Services”
  3. Click on “rsync”


On NAS 2:

Now, you need to create a sync task in the originating Synology:

  1. Click on “Control panel”
  2. Click on “Shared Folder Sync”
  3. Click on “Task list”
  4. and create a new task.


Now, lets give the task a name:


Now pick the folders you want to sync:

**Note that if the folder already exists in the destination NAS it will be renamed, otherwise, it will be created automatically.


Now it is time to connect to your destination NAS:

  1. Add ip address or server
  2. Add username
  3. and password
  4. and enable ssh and transfer compression
  5. Finally set block level synchronization so only new or modified files are synced.

2-step verification is not compatible with this feature.


Run sync on modification or manually:


and you are done!!


Having issues setting up rsync?

Please read this:

  1. Task name must be of 1 to 32 Unicode characters and must not contain the following characters:! ” # $ % & ‘ ( ) * + , / : ; <= > ? @ [ ] \ ^ ` { } | ~
  2. If you sync shared folders from ext4 to ext3 file system, you may encounter errors when the task contains over 32,000 folders.
  3. If the shared folders in the destination Synology NAS have been synced with other Synology NAS before, Shared Folder Sync will perform a full sync for the task.
  4. To perform Shared Folder Sync tasks, you need the admin privilege of the destination Synology NAS. Either you have its admin account’s password, or you are in the administrative group of it.
  5. When syncing to the destination Synology NAS over the Internet, you can enter the server name by its external IP address or its hostname. However, if you choose to enter its hostname, the name must be in FQDN (Fully Qualified Domain Name) format, like “”.
  6. For port-forwarding, Shared Folder Sync uses port 22 for encrypted transfer and port 873 for unencrypted transfer.
  7. External storage devices are not supported by Shared Folder Sync.
  8. When the Shared Folder Sync task runs, the encrypted shared folder(s) at the destination will be automatically mounted; however, to access the data inside, you must mount the encrypted shared folder(s) at the destination first.
  9. Scheduled Shared Folder Sync will not run at the specified time if no changes have been made to the selected shared folder.
  10. For best performance, we suggest each sync task includes less than 200 shared folders.
  11. The User Home function will be disabled on the destination Synology NAS if the homes shared folder is synced from the source Synology NAS to the destination Synology NAS.
  12. For models with non-Intel CPUs, you can sync up to 100,000 shared folders (including subfolders) using Shared Folder Sync.
  13. Shared Folder Sync can back up Windows ACL settings when the destination file system is ext4 or Btrfs.Note: Data and Windows ACL settings stored on Synology NAS can not be synced to EDS14.
  14. Shared Folder Sync will fail if you are syncing to a destination server which shares the same name as your Synology NAS.
  15. Advanced Shared Folder Permissions at the source will not be syncronized to the destination. Furthermore, a read-only rule for administrators group will be created at the destination.

10 thoughts on “Create snapshot of your Synology folders with Folder Sync (Part 3)

  1. Thanks @Ruth Pozuelo Martinez. This was what I searched for day.

    In addition, I noticed that the rsync speed decreases heavily with enabled transfer compression. I about 10 MB/s in that case.
    With disables transfer compression speed went up to 35 MB/s and may be been limited by my bad network connection between the two NAS.


      1. I guess I identified my bottleneck on that issue. My source is an old and weak 214play that is struggling to copy the folder. The folder is encrypted but I don’t know if this matters because it is copied as it is to the destination.
        Anyway the CPU usage is very high and transfer compression may make the situation even worse. So I guess this option is not recommended for powerless stations.

        I have not compared it with the cifs share copy method, because the network connection is my limitation now, so it will make no difference for me.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.