问一个haproxy+keepalived的奇怪问题

wangshuaiatwork

配了haproxy+keepalived做负载均衡，后面是两台nginx，确认keepalived的虚ip只在一台haproxy上，haproxy的策略是roundrobin，但是发现通过haproxy转发一个请求时，会同时转发到两台nginx，而不是轮询，有谁知道这可能是什么原因造成的？

haproxy的配置：

global
     maxconn 20480
     ulimit-n 65535
     daemon
     nbproc 1
     pidfile /var/run/haproxy.pid

defaults
     mode http

     log 127.0.0.1 local0
     option httplog
     option httpclose
     option forwardfor
     option dontlognull
     option redispatch

     retries 3
     timeout check 2000
     contimeout 5000
     clitimeout 5000
     srvtimeout 5000

     # stats
     stats uri /stats
     stats auth admin:admin
     stats refresh 10s
     stats realm haproxy\ statistic
     #stats admin if TRUE

frontend web
     bind *:80
     default_backend fdfs_lg_nginxcluster

backend fdfs_lg_nginxcluster
     balance roundrobin
     server nginx_192.168.56.91 192.168.56.91:81 check inter 2000 rise 3 fall 3 weight 5
     server nginx_192.168.56.93 192.168.56.93:81 check inter 2000 rise 3 fall 3 weight 5

haproxy.log:
Sep 18 13:18:46 localhost haproxy[20384]: 192.168.56.1:49971 [18/Sep/2014:13:18:46.261] fdfs-lg.dhapp.com fdfs_lg_nginxcluster/nginx_192.168.56.91 0/0/0/0/9 200 781045 - - ---- 0/0/0/0/0 0/0 "GET /g1/M00/1B/61/wKg4XVQRWYqAUSwEAAvqH_kipG8256.jpg HTTP/1.1"
Sep 18 13:18:46 localhost haproxy[20384]: 192.168.56.1:49972 [18/Sep/2014:13:18:46.318] fdfs-lg.dhapp.com fdfs_lg_nginxcluster/nginx_192.168.56.93 9/0/1/0/42 200 781045 - - ---- 0/0/0/0/0 0/0 "GET /g1/M00/1B/61/wKg4XVQRWYqAUSwEAAvqH_kipG8256.jpg HTTP/1.1"