I am trying to use syncthing to sync a directory of several million files, ~4 TB, between two machines. They are in different countries. Both ubuntu, both syncthing 2.0.12. One has the directory mounted on a fast local RAID, while the other has it mounted over a slow CIFS connection. The two sides are in sync initially, with rsync.
Initial scanning is ~15 hours on the RAID side, but looks like it could be a month or more on the CIFS side.
Long shot shortcut idea: is there any chance I could take the database files from the side that completes scanning, and copy them over to the other side?
You really should reconsider using Syncthing on a CIFS share. It assumes that accessing files is rather fast, thus is not well suited for network-based storage.
Unfortuantely, I don’t have a choice about the constraints I need to work under. And I will say syncthing works totally fine over the CIFS mount for more typically sized directories.