Backup plan · NAS server

How to configure Snapshot Replication on your Synology

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: One way sync for files and folders that do not change that often (cold storage).
  4. Snapshot Replication (this post): Snapshots 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 Synology replication which is my favourite form of back up and the one that saved me the most! (Probably that is why it is my favourite)

Snapshot Replication

Ok, so what is a snapshot? In simple words, it is like taking a snapshot of your data so you can go back in time and see how things looked like at different periods of time.

And what is a replication? Replication allows you to get your snapshots and copy them to other destinations, in other words, create a copy of your snapshots.


The following limitations apply to the snapshots:

  1. The folders have to use the Btrfs file system
  2. The following number of snapshots are allowed:
    • 1024 snapshots for each shared folder (or 256 on certain Synology NAS models)
    • 256 snapshots for each iSCSI LUN
    • 65536 snapshots in total in the system (or 4096 on certain Synology NAS models)

Overview of the Snapshot Replication application

To take snapshots of your folders,

  1. Click on Menu
  2. Click on Snapshot Replication

snapshot replication synology

and it will take you to:

  1. the overview of the snapshot replication where
  2. You can see how much data you have replicated and snapshots on
  3. and the last time a replication or a snapshot was done.

3 overview snapshot replication

If we click on snapshot, we will see all the snapshots we have done on this NAS and on which folders:

3 overview of snapshots synology

Take a snapshot:

If you want to schedule or take a new snapshot, you

  1. Click on snapshot
  2. To take a new snapshot, click on “Take a snapshot” (without scheduling, see below for more info on schedule snapshots)
  3. To see a list of snapshots taken click on “Snapshot list”
  4. To calculate the size of your snapshot click on “Calculate size”

4 take a snapshot synology

And fill in the following:

  1. Description of the snapshot
  2. Lock the snapshot so it doesnt get removed during the creation of new ones,
  3. Ok

5 snapshot description synology

Schedule snapshots on your synology

If you want to have your synology create snapshots at different points in time, you do like this instead:

  1. Click on snapshots
  2. Click on the folder you want to create a scheduled snapshot
  3. Click on Settings

6 schedule snapshots synology

On the Schedule tab, select your schedule settings:

  1. How often ( I pick daily)
  2. Frequency: every day
  3. and when the snapshot should be done ( I always pick at night, so all the work has be done and it is ready for a backup)

7 snapshot schedule settings synology

On the retention tab we specify how often the snapshots should be retained.

Here I always set my own retention schedule, which is 1 snapshot daily, weekly, montly and yearly. The is enough for my needs.

8 retention policy snapshots synology Last but not least you can specify if you want the snapshot taken at GMT 0 (if your synologies are in different time zones) and if you want to make the snapshots visible.

9 snapshot schedule advance settings synology

Once you have configured the snapshots, you can check the settings on the main menu:

10 overview of snapshot of shared folder synology

And to see the snapshots, you:

  1. navigate to your folder
  2. Expand the snapshot folder
  3. and you will see all the snapshots you specified before
  4. and if you expand on of them you will see the actual files

11 snapshots of your folders synology

Easy right? This little functionality has saved me countless of times when deleting things a bit too fast!!!

This post is running too long, so I will go through the replication settings in another post.


Have fun, enjoy your Synology and Happy New Year!!!


I am buying my third synology in January, so I will run a series of posts on how to configure your synology from scratch very soon, Stay tuned!!






21 thoughts on “How to configure Snapshot Replication on your Synology

  1. Hi Ruth, always look forward to your emails. Waiting in anticipation for your replication part. I seem to have done it the wrong way round. I’ve done replication but struggling with snapshots, I need to start from scratch. Best regards from the UK.


  2. Great articles, I just bought my second synology after a near disaster nearly wiped all my data. Never rely on RAID protection as backup strategy! What I am still struggling with is a mental model for whic tech I use and when and why. At the moment .i am doing hyperbackup to hyper vault. I don’t mind it needs hyperbackup explorer. But snapshots with replication seems like it might be faster…. I am super confused. Do you have recommendations on what to choose when?


  3. What do you mean by ‘3. A replication on important folders’?

    I’m looking at using Cloud Station ShareSync, but saw in this post ‘and the replication makes hourly, daily, weekly, quarterly and yearly copies of it’

    Is this with Cloud Station ShareSync or another app? (Maybe Snapshot Replication?) I’m interested in syncing to my second Synology (offsite) with Cloud Station ShareSync but am also interested in ‘A replication on important folders’.

    And you still use Hyper Backup for some things, alongside Cloud Station ShareSync?
    I was thinking of syncing files (mainly work) to the 2nd NAS with Cloud Station ShareSync, but maybe just using Hyper Backup for larger, less frequently modified files (mainly media).

    Liked by 1 person

    1. Hi Jono,
      Yes, snapshot replication is another app that you can install in your NAS.
      This is how I do, I sync my folders to my external slave NAS with sharesync and then I activate the snapshots in the slave, so I dont have that hit of perfomance when I work. If I lose a file, I go the slave and recover it from there.
      I still use hyperbackup to backup all my NAS files. ( i only use snapshots n in some folders).
      Hope this helps!, I will be doing a post in replication very soon.


  4. Ruth,

    Great posts. I have 2 units myself and support about 20+. I am having doubts with the “seeding” of the first replica as it is quite big to be sent over the net. The replica is locally created in the source unit. Now what?


  5. Are you able to write some details on the Snapshot Recovery processes? There are a few options to choose, and unfortunately Synology’s documentation doesn’t say much.


  6. Nice guide but it would be good to also cover remote “Snapshot Replication” since the guide currently only covers taking local snapshots – Remote Snapshot replication (especially across site and with each NAS behind its own router) is not really covered well/at all on Synology’s website.


  7. I am trying to understand how snapshots work. I have a folder containing a little less than 1TB of video files and the size of it’s snapshot is 3.5 GB. Does this mean that the snapshot can restore those files if all of them are corrupted or deleted? Very nice blog by the way. I visited your corporate site and it is amazingly tidy!


      1. I don’t think my DS218+ is copying the entire contents of the folder because I’ve had scheduled snapshots for almost a month now and I can see a list of all of them when I click the ‘Snapshot list’ button. When I click the ‘Calculate size’ button in the ‘Snapshot’ Replication’ app, it works for maybe 15 or 20 seconds and comes up with this figure. I’ve been considering doing a Replication as an exercise to see what happens but I’m afraid of messing up the files. I guess I have more research to do. Thanks.


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