The following are two graph of my digital ocean vps instance handle load test request. 10K/s, The only different is the request file size, first is 10K, the second is 20K. Can any one point out the bottle neck of my server setup?
P.S resources peak usage: CPU 20%, memory 10% Network IO 69MB/s(This may the problem lies) Disk IO 0.13%
DigitalOcean 8-core instance 16G RAM, using Nginx serving static 10k/20k image file.
update! I put load balancer(HAProxy) into a separate VPS(8 core), I found the cpu usage is pretty high as the 3rd gram shows(5k request on 10k image)