I recently started to notice following error messages on my openVPN server.ovpn-server: vpn.rootspirit.com/85.234.x.y:62068 MULTI: packet dropped due to output saturation (multi_process_incoming_tun)
This basically means that the TUN or TAP interface is making more packets than the real (TCP) interface can handle.
As I need to run OpenVPN using the TCP protocol (instead of the faster UDP protocol; as UDP is often blocked in networks I use my VPN in) I experimented by increasing the tcp-queue-limit. The default is 64, and I’ve set it to 256. So far, everything still seems to be working fine (but more packets will be queued before being dropped by OpenVPN, requiring less retransmissions).
Add this to the OpenVPN server config:tcp-queue-limit 256
And restart the daemon.