Sync conflict, downloading instead of uploading

Nextcloud version (eg, 12.0.2): 17.0.1
Operating system and version (eg, Ubuntu 17.04): Ubuntu Server 18.04.3
Nextcloud Client: 2.6.1 on Linux Mint 19.2

I try to backup files to a nextcloud server at my parents house.
I get sync conflicts (copy gets downloaded from the server) or data is just downloaded from the server at random, causing unnessesary disk degradation.
Maybe it is because the data folder is completely switched out by my backup mechanism (rsync with hardlinks) on a daily basis via mv command, so backup.daily.2 becomes backup.daily.3 once a day. daily.3 is the folder that is getting synced instead of the live data as a little pracaution für eventual ransomeware infection.

Somebody got an idea what is going wrong there?

In general (or if i can not get this fixed) it would be good to have an option to force the client to upload (client -> server) instead of downloading (bi-directional). I use FolderSync on Android to sync some files, and i can tell it to either go client>server, server>client or bidirectional, is this possible with the client, too? this should be an option in the client, but i didn’t find one, maybe there is something i can change in the config-file of nextcloud client?



seems like this is not gonna be answered … do i need to provide more info? if so what information?

It has been 3 months now and nobody has even the slightest hint for me what i could do?
I am not able to back up my files so this is a huge issue for me …

In the meantime I upgraded the Client to LM19.3 and NC Client to 2.6.4 and also the NC Server Version was bumped to 18.0.4. So all in all, the normal upgrade stuff, but I don’t think this has sth. to do with it.
What I did find out though is that while the files themselves do not change during the mv command (as they hardlink to the same file), the hidden NC Client files (.sync*) get moved away and need to be rebuilt by the NC Client. That seems to be the root cause of this issue. Aditionally I forced NC Client to stop (kill $(pgrep nextcloud) ) before the mv command and start it again afterwards (nohup nextcloud > /dev/null 2>&1 & disown) to prevent problems during the mv command.
I had it sync for 4 days to finish and let it sync the incoming new differences for 3 days and no issues so far, so this seems to solve the problem.

Still I would find an option to choose the sync direction to be useful.

Nextcloud isn’t a backup solution, it is a sync solution, you want to keep data in sync over different devices. That is a different objective. Honestly, why do you use Nextcloud for this at all. I also do backups, rsync is a nice tool but not suited for Nextcloud directly (links are not handled well, there is no sync direction).

Why don’t you just put a pretty plain linux system at your parents place and use rsync over ssh to put your backup? Such solutions are widely used, tested, reliable and much faster than passing through Nextcloud.
If you want Nextcloud as interface to access data, you can just use it to access the backup folder (ideally as read-only).

I use nextcloud for it because it works best for my use case.
I have sevaral nextcloud instances in my family anyways which they use for themselves, why not use it to backup from my own nextcloud via nextcloud client like described above.
It is way easier than installing a separate linux system (though I could use the linux system under their nextcloud systems) and figuring out how to do rsync over ssh reliably for hundreds of GB with a slow connection (no idea how to rate limit that), and I would need to worry about exposing ssh on the home router at my parents house also.
Instead I just install nextcloud client and done (well almost, had to figure out that i have to stop nextcloud during mv command).

The issue is resolved for my use case now, but still I think this would come handy for other people to decide in which direction the sync should go. My knowledge is fairly limited but my naive understanding would be that this option should not be that hard to implement. It should “only” be a “shortcut” whilst comparing files on both sides and deciding which one should be picked, could even result in a performance improvement if someone just wants to sync in one direction and this check is left out, right?