Avoid network traffic jam with BBR
From time to time, here or there, we see subjects flourish on an abnormally limited speed in FTP.
To overcome this kind of slowdown, simply activate the TCP BBR protocol
Without going into details, this protocol makes it possible to make better use of the bandwidth available during the exchange of TCP packets. Created by Google, you can find more information here.
Integrated into the Linux Kernel since version 4.9, all you have to do to activate it is to edit the kernel parameters (/etc/sysctl.conf) and add :
net.ipv4.tcp_congestion_control = bbr net.core.default_qdisc = fq
A TCP command acting in both IPv4 and v6,
save and load with :
sudo sysctl -p
And we go from a restricted FTP speed
If you are under Proxmox or ESXi, this must be done both on the host and in the VM/CT.