nginx upstream set 2 tomcat links:

upstream tomcats {
server localhost:8080 max_fails=3 fail_timeout=3s;
server localhost:8081 max_fails=3 fail_timeout=3s;

}
server {
listen 80 default;
server_name localhost;

charset UTF-8;

location / {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://tomcats;

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size 50m;
client_body_buffer_size 256k;
proxy_connect_timeout 10;
proxy_send_timeout 60;
proxy_read_timeout 60;
proxy_buffer_size 128k;
proxy_buffers 8 128k;
proxy_busy_buffers_size 128k;
proxy_temp_file_write_size 128k;
proxy_max_temp_file_size 128k;

}
}


at run ab.exe or webbench is slow,but the static html page is very fast.
static html page can run 9000 request/m,but upstream's 2tomcat is slow.

when i run
ab -n 20000 -c 1000 http://192.168.0.242/CStar/LEAP/CStar/HTML/Login.html

visit has block at: http://192.168.0.242:80/CStar/LEAP/CStar/HTML/Login.html
visit tomcat is succeed at: http://192.168.0.242:8081/CStar/LEAP/CStar/HTML/Login.html
or http://192.168.0.242:8082/CStar/LEAP/CStar/HTML/Login.html

some time visit 1 tomcat has block,but the other one has succeed,always the nginx is block.

when the ab run end,the nginx some times is block little,some times is ok.

[b]please help me.[/b]

[b]the full config file:[/b]

user tomcat tomcat;
worker_processes 2;
#worker_cpu_affinity 00000001 00000010;

error_log /var/log/nginx/error.log notice;

pid /var/run/nginx.pid;

worker_rlimit_nofile 2048;
events {
use epoll;
worker_connections 2048;
}


http {
include mime.types;
default_type application/octet-stream;
source_charset UTF-8;
server_names_hash_bucket_size 256;
client_header_buffer_size 4k;
large_client_header_buffers 4 4k;

#open_file_cache max=65536 inactive=20s;

#size limits
client_max_body_size 50m;
client_body_buffer_size 256k;
client_header_timeout 3m;
client_body_timeout 3m;
send_timeout 3m;

#参数都有所调整.目的是解决代理过程中出现的一些502 499错误
sendfile on;
tcp_nopush on;
keepalive_timeout 120; #参数加大,以解决做代理时502错误
tcp_nodelay on;




upstream tomcats {
server localhost:8080 max_fails=3 fail_timeout=3s;
server localhost:8081 max_fails=3 fail_timeout=3s;

}

server {
listen 80 default;
server_name localhost;

charset UTF-8;

location / {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://tomcats;

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size 50m;
client_body_buffer_size 256k;
proxy_connect_timeout 10;
proxy_send_timeout 60;
proxy_read_timeout 60;
proxy_buffer_size 128k;
proxy_buffers 8 128k;
proxy_busy_buffers_size 128k;
proxy_temp_file_write_size 128k;
proxy_max_temp_file_size 128k;

}
}

server {
listen 81;
server_name localhost;

charset UTF-8;


location / {
root /f/yumserver;
index index.html index.htm;
}


error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}




}