Big difference between upstream response time and request time

[Praveen]

Hi,
I'm using nginx as a reverse proxy to my backends. I see there is a
huge discrepancy between upstream response time and request time.

X.X.X.X [15/Oct/2008:09:32:57 -0700] "GET /js/something.js HTTP/1.1"
upstream_response_time 0.005 request_time 105.026 90732578
10.3.0.134:8000

It's generally negligible. But sometimes its as high as 5 or more
seconds, and in some cases as high as the example above.

Any idea what's happening? nginx is running on a dedicated server, and
has about 2000 active connections.

worker_processes  4;
worker_connections  4096;

keepalive_timeout   120;
send_timeout          90;

proxy_read_timeout  120;
proxy_buffer_size   8k;
proxy_buffers   32 32k;

Thanks.

--
Praveen