I have an nginx server (CentOS 5.3, linux) that I'm using as a reverse-proxy load-balancer in front of 8 ruby on rails application servers. As our load on these servers increases, I'm beginning to wonder at what point will the nginx server become a bottleneck? The CPUs are hardly used, but that's to be expected. The memory seems to be fine. No IO to speak of.
So is my only limitation bandwidth on the NICs? Currently, according to some cacti graphs, the server is hitting around 700Kbps ( 5 min average ) on each NIC during high load. I would think this is still pretty low.
Or, will the limit be in sockets or some other resource in the operating system?
Thanks for any thoughts and insights.
Thank you for your insights. I have done a little more digging. I have 1 worker allowing 1024 worker_connections. Let's assume that 95% of the requests are for small amounts of data. Any recommendations on what a system with 512MB should be able to handle, connections wise?
Also, what's a good way to count connections? Would something like this be accurate?:
netstat -np | grep ESTABLISHED | grep nginx | wc -l