We installed the nextcloud server on a cloud service provider 's VM and they just reported to me yesterday that the vm is lost due to hardware failure and also the backups are gone also!
The only way I can do is to re-install nextcloud on a new VM.
After setup and re-created all users, we found that when user re-login to the new server (with desktop client or mobile app), their files in the local sync folder will be removed by the client.
Maybe it is because the newly installed server does not have any user files and the sync client just remove all files in the local folder after sync.
Is it possible to have any setting in server configure or in the client program, to make the sync client to push back the files to server from client if the sever folder is empty?
I not a 100% sure but I don’t think so… But regardless of that I would play safe, rename the existing sync folder to Nextcloud_old or similiar and delete the account in the sync client. After that you can recreate the account and it will then create a new sync folder. When the connection is established again, you can move the files from Nextcloud_old to the newly created Nextcloud sync folder and they should be uploaded to your new server.
Hm I would rather say no, respectively it most likely makes not too much sense. The mobile apps don’t do a full sync like the desktop client does. So if people no longer kept these files on their devices after they uploaded them to the Nextcloud via the app, or have theme stored elswhere, these files ar most likely gone for good.
The path where the mobile client stores the files can be seen in the settings of the app, at least on Android. Unfortunately, I don’t know much about the iOS app, but it should work the same in principle. But don’t expect to find the complete content of the former Nextcloud in this folder. This folder is rather meant as a cache for files that users have marked for “offline usage”, than as a real sync folder like in the desktop client. But I guess it is probably worth to have at least a look at it.
Btw. the same applies if some users have used “Virtual Drive” on their Desktop computers or when they have excluded individual folders from the synchronization.