Boost Nginx Performance: Custom 404 Pages, Status Monitoring, and Concurrency Tuning

Nginx is a high‑performance web and reverse‑proxy server widely used by major Chinese companies such as Taobao, JD, Baidu, Sina, NetEase, and Tencent.

1. Custom 404 error page

Before optimization, accessing a non‑existent page shows the default 404 message. # firefox http://192.168.4.5/xxxxx After editing /usr/local/nginx/conf/nginx.conf to add error_page 404 /404.html; and creating a custom 404.html, reload Nginx.

# vim /usr/local/nginx/conf/nginx.conf
... error_page   404  /404.html;
# vim /usr/local/nginx/html/404.html
... (custom content)
# nginx -s reload

Now the client sees the defined 404 page.

2. View server status information

Enable the stub_status module during compilation with --with-http_stub_status_module and add a location block:

# tar -zxvf nginx-1.12.2.tar.gz
# cd nginx-1.12.2
# ./configure ... --with-http_stub_status_module
# make && make install
# /usr/local/nginx/sbin/nginx
# netstat -anptu | grep nginx
# ss -anptu | grep nginx

Define the status page in nginx.conf:

location /status {
    stub_status on;
    #allow IP;
    #deny IP;
}

Access http://192.168.4.5/status to see metrics such as Active connections, accepts, handled, requests, Reading, Writing, and Waiting.

3. Increase Nginx concurrency

Before tuning, an ab test shows “Too many open files”. # ab -n 2000 -c 2000 http://192.168.4.5/ Modify nginx.conf to match CPU cores and raise connection limits, then reload.

# vim /usr/local/nginx/conf/nginx.conf
worker_processes 2;               # same as CPU cores
events {
    worker_connections 65535;    # max connections per worker
}
# /usr/local/nginx/sbin/nginx -s reload

Adjust Linux file descriptor limits:

# ulimit -a                     # view current limits
# ulimit -Hn 100000            # set hard limit (temporary)
# ulimit -Sn 100000            # set soft limit (temporary)
# vim /etc/security/limits.conf
* soft nofile 100000
* hard nofile 100000

4. Increase request header buffer size

Before adjustment, a script generating a very long URL triggers “414 Request‑URI Too Large”.

# ./buffer.sh
<center><h1>414 Request-URI Too Large</h1></center>

Update the http block:

http {
    client_header_buffer_size 1k;
    large_client_header_buffers 4 4k;
}
# /usr/local/nginx/sbin/nginx -s reload

5. Browser local cache for static assets

In Firefox, open about:cache to view and clear the cache. Define a 30‑day expiration for static file types in Nginx.

# vim /usr/local/nginx/conf/nginx.conf
server {
    listen 80;
    server_name localhost;
    location / {
        root html;
        index index.html index.htm;
    }
    location ~* \.(jpg|jpeg|gif|png|css|js|ico|xml)$ {
        expires 30d;    # client cache for 30 days
    }
}
# nginx -s reload

After reloading, verify caching by accessing an image and checking about:cache again.