I have two Ubuntu servers (ie. no GUI) that I need to synchronize files across a WAN connection, on an ongoing basis. So far, I've tried BitTorrent Sync and Syncthing, but they are painfully slow. Using rsync, I'm able to synchronize files at over 12 MBps (which is about 90% of my available bandwidth), but using either of the above named tools, I may get a measly 1-3 MBps.
Recently I discovered websync, which is a web-based frontend for rsync, which was promising but is very painful to set up and ultimately too challenging for me. I could not get it to work properly.
Are there any file synchronization tools that have a web-based GUI and offer the speed that SCP or rsync do?