worker_connections exceed open file resource limit: 256

2014/10/07 03:47:36 [warn] 8360#0: 1024 worker_connections exceed open file resource limit: 256
2014/10/07 05:47:37 [warn] 11899#0: 1024 worker_connections exceed open file resource limit: 256
2014/10/07 07:47:38 [warn] 15415#0: 1024 worker_connections exceed open file resource limit: 256

阿里云服务器，Tengine 1.5.2
[root@sev nginx]# ulimit -n
65535
[root@sev nginx]# ulimit -u
65535
[root@sev nginx]# cat /proc/sys/fs/file-max
99103

同样配置在Nginx1.6.1下无警告