nginx reverse proxy proxies subset of requests slowly

[Maxim Dounin]

Hello!

On Mon, Feb 20, 2012 at 12:59:38PM -0500, anonymous_coward wrote:

> (This is cross-post from Server Fault:
> http://serverfault.com/questions/361742/nginx-reverse-proxy-proxies-subset-of-requests-slowly)
> 
> We're running an nginx reverse proxy in front of a couple of IIS 7.5 web
> servers. I'm benchmarking a particular page using Apache Bench. The page
> is fully cached in memory in IIS (using ASP.NET outputcache). No caching
> is configured for nginx.
> 
> We've noted a discrepancy in the benchmark results between runs straight
> up against one IIS server (no reverse proxying) and with an nginx
> reverse proxy in between. With the proxy in place, for non-trivial
> loads, a subset of requests take very long to complete. Without the
> proxy in place, all requests are completed in reasonably good time.

[...]

> **nginx**
> 
> 	user at host:~$ ab -n 5000 -c 1000 [NGINX-HOST]

[...]

> 	Concurrency Level:      1000

Under which OS you run nginx?  Please note that 1000 is too high 
for nginx on Windows, see known issues list here:

http://nginx.org/en/docs/windows.html#known_issues

If running nginx under Windows, please also make sure you have 
worker_processes set to 1.

Maxim Dounin