it said ""aio on" is unsupported on this platform in /usr/local/nginx/conf/nginx.conf:25" when i apply my conf.

see version info bellow:

[root]# /usr/local/nginx/sbin/nginx -v
nginx version: nginx/1.10.3

[root]# lsb_release -a
LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 6.8 (Final)
Release: 6.8
Codename: Final

[root]# uname -a
Linux nginx-ppr1-public-a1 2.6.32-696.3.2.el6.x86_64 #1 SMP Tue Jun 20 01:26:55 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux