Avoid complete nextcloud resync to client if data are already on the client (via rsync)

over a long run of time I gathered may photos (140GB). The master copy of these data resides on my home nextcloud server and is synced via nextcloud client on a local linux system via a 1Gb link to the nextcloud server. To avoid data loss I also mirrored these data to another remote linux host using unison and/or rsync.

The problem is that the network link between those two linux hosts is slow (2Mbit/sec) which is not a problem as long only new data have to be synced.

Now I would like to try to also use the nextcloud client for this sync process. All the data are already on the destination client in the correct subdir of nextcloud tree. Up to now I told the nextcloud client not to sync this sub directory.

I could of course start a full sync via nextcloud client but this would take close to an eternity because of the slow network link.

Therefore I ask myself if there is any way to to tell the nextcloud client that all the data is already there and up to date.

Any ideas?

This was a major issue for quite some time with only some workaround (not sure if they work very well): https://github.com/owncloud/client/issues/3422 (and linked issues).

ownCloud now uses hashes and solved this issue probably: https://github.com/owncloud/client/pull/5838
I’m not sure if the patch has been backported and if the hash-sum stuff works like this in Nextcloud. Check the Nextcloud bug tracker (https://github.com/nextcloud/desktop) if your issue has been tracked, if not add a new report, perhaps add the one how ownCloud fixed it.