I’m trying to setup Syncthing between two machines, and my goal is to share a single very large folder (over 1TB).
As I don’t want machine #2 to re-download everything from scratch, I made an initial copy of the folder using an USB drive and put all the files in place “offline”.
Will it work?
More explicitly: does Syncthing scan the local folder first, and only then attempt to download what’s missing?
Additional question: I assume that Syncthing will check if a local file matches by checksum. What would happen, for example, if the local file is identical to the remote but the file date is different?
Syncthing checks for local changes based on size and mtime (and permission), and if there is a change hash to compare by checksum.
It will regard everything as a conflict (as the same files appear on two devices at the same time), and resolve those without conflict copies for identical items and items which only differ in metadata (i.e. permissions and mtime) - newer mtime wins. In the UI it will show up as “Syncing”, but that doesn’t mean it’s necessarily syncing data, in your case it will just be exchanging and comparing metadata.