Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!


Fixing Network Speed in KVM - Page 2
New on LowEndTalk? Please Register and read our Community Rules.

All new Registrations are manually reviewed and approved, so a short delay after registration may occur before your account becomes active.

Fixing Network Speed in KVM

2»

Comments

  • netomxnetomx Moderator, Veteran

    TimboJones said: people just stopped tweaking because there's trade offs and requires testing

    @hyperblast

  • Setting the TCP window sizes requires estimating the Bandwidth-Delay product (BDP) : https://web.archive.org/web/20080803082218/http://dast.nlanr.net/Guides/GettingStarted/TCP_window_size.html

    To deal with lossy connections, you need to decrease window sizes and to deal with high bandwidth or high round-trip times increase window sizes. Also take RAM into consideration, because these settings apply to each TCP connection.

    For a 512MB VPS running a webserver, I just push up the minimum values to speed up window autonegotiation.

    net.ipv4.tcp_wmem = 10240 87380 12582912
    net.ipv4.tcp_rmem = 4096 87380 12582912
    

    For my home router, I push up tcp_rmem over tcp_wmem instead. There's also net.core.rmem/wmem which applies to queues across all protocols.

    If your kernel supports BBR, definitely enable it.

    Thanked by 2Daniel15 coreflux
  • @hyperblast said:
    no suggestions about using "hack" + bbr? is combination of both recommended or not?

    That's up to you. If your server has a single purpose, you can optimize for that. If it's a general use server, then don't worry about it.

    It really comes down to need, squeezing out the last few percent of possible performance. If you're getting acceptable speeds, call it a day.

    If you're stuck with certain hardware and can't handle concurrent users, then you can optimize and improve that. Especially, if you have tons of available ram.

Sign In or Register to comment.