Hi. I am using Syncthing essentially to back up a computer to a Synology NAS. I now have it set as “send only” on the computer and “receive only” on the NAS. I am paranoid that something will happen on the NAS which will mess up the computer so I have this one-way setup. Very occasionally, I may want to make a change on the NAS (such as deleting a file) which I will want to propagate to the computer. In this case, would it be ok to change the computer setting to have it on “send and receive” at all times, and just temporarily toggle on the NAS from “receive only” to “send and receive”? Am I risking anything this way?
And related to that: let’s say I delete a file on the NAS when it is set to “receive only”. When I then change it to “send and receive” will it delete the file?
FYI: You do not have a backup on the NAS. You have a synchronized copy. Deletions and editions (by purpose or by mistake or by malware) on the computer will be propagated to the NAS.
Bad stuff could also happen with your files on the NAS. Imagine that ransomware encrypted files on the NAS. The moment you make it “Send & Receive”, those edits will be sent to others.
You may want to only set the computer to send-only, but keep the NAS send-receive. That’s enough to “protect” your computer from accidental changes. But it causes a warning to appear on the computer when anything is changed on the NAS. You then have the opportunity (a GUI button) to override the changes and force the NAS to look like your computer again, or you can switch to send-receive and thereby accept the change from the NAS. Of course any other changes during that time will also get applied. So manually deleting the “out of sync” file you had already deleted on the NAS would be the safer way.
Oh, and what @martinleben said: Syncthing is not a good backup tool! It just serves a different purpose (excellently).
Just a side note, but reading just the above, I’d say you definitely want to set up Versioning, at least on the computer if not on both sides . I’d also suggest implementing a proper backup solution on top of the above to make sure your data is actually secured.
. I’d also suggest implementing a proper backup solution on top of the above to make sure your data is actually secured.