What happen to files when server get restored from old backup?

ℹ️ Support
1

Let’s say that:

  • I have a server hosting a nextcloud instance
  • After a power failure, server hard drive died and I lost all data on this server
  • As everyone (need to) do, I have a backup from 2 weeks ago

Now what I want to know is:
If I restore this 2-weeks-ago backup, what happens to files that has been synced between backup and now?

  • will they be automatically synced again by NxC client? or
  • will client-side files be deleted for files that does not exist on the server (“shoud already be synced” files are not present server-side so client may take it as “has been deleted from elsewhere”)?

Thanks.

1 Like
2

I didn’t find anything related to it on the NxC doc (well, that was expected since it’s a very specific problem)

3

https://docs.nextcloud.com/server/17/admin_manual/configuration_server/occ_command.html#maintenance-commands

After restoring a backup of your data directory or the database, you should always call maintenance:data-fingerprint once. This changes the ETag for all files in the communication with sync clients, allowing them to realize a file was modified.

I don’t know how exactly the client behaves. I’d save the whole folder on an extra-drive, disconnect this drive, and then run the client with the backed-up server again.

4

mhh, for what I understand, maintenance:data-fingerprint makes files in cloud the ones to be kept (the “allowing them to realize a file was modified” part) where I want the other way around…