nginx: [emerg] could not build the server_names_hash

手头有块板子，上面起了nginx配置了多个域名，启动的时候发现报错：

nginx: [emerg] could not build the server_names_hash, you should increase server_names_hash_bucket_size: 32

大致意思说是域名build不了了，因为空间不够，需要increase域名的size。
这里是官方的解释：

http://nginx.org/en/docs/http/ngx_http_core_module.html#server_names_hash_bucket_size

还有中文的

https://wiki.archlinux.org/index.php?title=Nginx_(%E7%AE%80%E4%BD%93%E4%B8%AD%E6%96%87)&mobileaction=toggle_view_mobile