Slow single TCP connection
Hey, I have problem with 4 dedis I got from Hetzner.
All of them max out at 8-10Mbps on single TCP connection.
iperf, http1.1, http2, sftp - doesnt matter, I get 8-10Mbps maximum if its just a single TCP connection.
There is no problem when I start multiple connections on iperf or http via IDM which can open multiple connections over TCP - transfers can easily go to hundreds of Mb/s then.
I have this problem on both Debian 11 and Ubuntu 22.04
Zero impact from:
- Turning up MTU from 1500 to 9000
- Turning on BBR
- Disabling UFW
- Compiling Nginx from source with AIO (so I tried directio, aio threads and sendfile, no difference, it is always 9-10Mbps when sending big files)
- Using different "client" machine on different network
- Increased buffer size like suggested here https://www.cyberciti.biz/faq/linux-tcp-tuning/
For comparison Oracle Free Tier shitty x86 1/8OCPU instance gets 25Mbps, MTU is on 9000. Its on CentOS7, maybe thats the cause?
There's no way dedi cant reach these speeds... I'm clearly missing something
Or does Hetzner limit single TCP connection speed somehow and Im just wasting time?
2x AX41 - Ryzen 5 3600, 64GB ram, 2x 512GB NVMe etc.
2x SX162 - E5 1650V3, 128GB ram, 10x 10GB HDD etc.
CPU usage is like 1%.