I fixed it.
Just only copy below to Advanced tab when create website

# Support Clean (aka Search Engine Friendly) URLs
location / {
try_files $uri $uri/ /index.php?$args;
}

# deny running scripts inside writable directories
location ~* /(images|cache|media|logs|tmp)/.*\.(php|pl|py|jsp|asp|sh|cgi)$ {
return 403;
error_page 403 /403_error.html;
}

# caching of files
location ~* \.(ico|pdf|flv)$ {
expires 1y;
}

location ~* \.(js|css|png|jpg|jpeg|gif|swf|xml|txt)$ {
expires 14d;
}

I tested Ajenti and AjentiV.
free -m told me it takes below 200MB RAM under Debian 7 32bit
The total system is only 1.1GB (without swap)

Hope AjentiV has more functions like Centos Web Panel