Don't use Pound for load balancing
By Emmett on Monday, March 3 2008, 18:35 - Permalink
We were using Pound for load balancing at Justin.tv until today. It was consistently using about 20% CPU, and during spikes would use up to 80% CPU. Under extremely high load, it would occasionally freak out and break.
We just switched to Ngnix, and load immediately dropped to around 3% CPU. Our pages feel a little snappier, although that might be my imagination. Not only is the config format easier to understand and better documented, but it offers a full webserver's complement of functionality. We haven't hit any spikes yet, but given the current performance I suspect it will cream pound.
In short: Pound is out-dated. Nginx is a good replacement, although there are many, many, many other options I haven't tried.
Edit: More data now available!
Comments
Great post, Emmett!
nginx is great with both memory and cpu usage. been using it on http://skribit.com for a while now.
I recall reading something similar last year and ended up deploying http://rankforest.com with just Nginx. Good to see some hard data from someone with a site that surely gets heavy traffic.
Beware the naive round-robin load balancing! If one of your processes hangs, it will keep queuing requests on it - even though all other processes might be doing nothing.
There's an experimental "fair" load balancing plugin - we've had reasonable luck with it.
We are using LVS for loadbalancing and it seems that it almost doesn't need any cpu time at all, even at peaks it doesnt go over 5% (on a P4 3Ghz) and peaks are like 2K requests per second.
Thanks Jason...I'll look into using that plugin.
I use nginx as back-end and it works great :)
Thanks for graphs with pound!