Performance with Intel i218/i219 NIC
I always had the feeling that my server, hosted by Hetzner, somehow has a slow internet connection. Then, I did put it on the distance between Finland and Japan, and didn’t care too much. Until yesterday my server stopped reacting to pings/ssh, and needed a hard reset. It turned out that the server was running fine, only that the ethernet card did hang. Hetzner support answered promptly and directed me to this web page, which described a change in the kernel concerning fragmentation offloading, and suggested the following configuration to regain connection speed:
tso off gso off
And to my surprise, this simple thing did wonder, and the connection speed improved dramatically, even from Japan (something like factor 10 in large rsync transfers). I have added this incantation to system cron tab and run it every hour, just to be sure that even after a reboot it is fine.
If you have bad connection speed with this kind of ethernet card, give it a try.