File synchronisation between 2 servers

Hi all,
we have 2 fileservers running ZFS with sanoid and syncoid. Server 1 is main server and server 2 is backup. In case server 1 goes down, the server 2 is taking over its IP so all the NFS shares are still availible. So far so good… the issue is, if the server 1 goes down for a few days, how do we resync everything back? We are talking about 200TB of data, so I would like a system that doesnt resyncs everything, but rather checks whats there and resyncs only the changes.

I was also wondering if TrueNAS Core had such a feature, since I would really love to replace our current system with TrueNAS Core.


I have never used sanoid and syncoid nor I am not aware of any automatic way to have TrueNAS Core or Scale do that. One option that might work is Sycnthing as it does support synchronizing data between locations.

For migrating file servers I often use ViceVersa Pro. I don’t typically use it to sync changes back from the target to the source but it has that option.

This would force you to use SMB or NFS as opposed to something native to ZFS.

They also have a separate license for their VVEngine, which is a service that watches for changes and automatically runs the ViceVersa profile when a change happens. We use this as often we’ll have a split where some users are writing to the old file server while other users are writing to the new file server.

Thanks for the feedback!
Ill look into them.