my-docs/Web-Servers/Nginx/10-Optimization.md

Nginx Optimization Guide

This document provides recommended configurations to optimize Nginx performance for high concurrency, low latency, and efficient resource usage.

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1. Core Performance Configuration

worker_processes auto;
worker_rlimit_nofile 65535;

events {
    worker_connections 8192;   
    multi_accept on;          
    use epoll;                 
}

Explanation:

Directive	Description
worker_processes auto	Automatically sets the number of worker processes to match CPU cores. Best practice: match number of CPU cores.
worker_rlimit_nofile 65535	Increases the number of file descriptors (FD) Nginx can handle, supporting higher connections.
worker_connections 8192	Maximum number of simultaneous connections a worker can handle.
multi_accept on	Allows a worker to accept multiple new connections at once. Improves performance but increases CPU usage.
use epoll	Uses the epoll event model (Linux only). Highly scalable and efficient for non-blocking I/O.

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2. HTTP Optimization

http {
    sendfile on;               
    tcp_nopush on;             
    tcp_nodelay on;            
    keepalive_timeout 65;      
    keepalive_requests 10000;  

    client_max_body_size 50M;  
    server_tokens off;         

    # Compression
    gzip on;
    gzip_comp_level 5;         
    gzip_min_length 256;
    gzip_proxied any;
    gzip_types text/plain text/css application/json application/javascript application/xml+rss;
}

Explanation:

Directive	Description
sendfile on	Sends files directly from disk to network (zero-copy). Reduces CPU usage and improves response time.
tcp_nopush on	Sends headers and body together in a single packet for better network efficiency.
tcp_nodelay on	Sends small TCP packets immediately, reducing latency for small responses.
keepalive_timeout 65	Keeps connections open for 65 seconds after a request (adjustable).
keepalive_requests 10000	Maximum number of requests allowed per keepalive connection.
client_max_body_size 50M	Limits maximum upload size to prevent DoS attacks.
server_tokens off	Hides Nginx version in headers and error pages for security.
gzip on	Enables gzip compression of responses to reduce bandwidth.
gzip_comp_level 5	Compression level (1 = fast, low compression; 9 = slow, maximum compression). 5 is a balanced choice.
gzip_min_length 256	Only compress responses larger than 256 bytes.
gzip_proxied any	Enable compression even behind reverse proxies.
gzip_types	Defines content types eligible for compression.

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3. Static File Caching

location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff2?)$ {
    expires 7d;
    access_log off;
    add_header Cache-Control "public, no-transform";
}

Explanation:

Directive	Description
`~* .(jpg	jpeg	png	gif	ico	css	js	woff2?)$`	Regex to match static files (images, styles, scripts, fonts).
expires 7d	Sets browser caching for 7 days to reduce server load.
access_log off	Disables logging for static files to improve performance.
add_header Cache-Control "public, no-transform"	Ensures files are cacheable by clients and proxies.

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Summary of Best Practices

1. Worker & Connection Optimization: Match workers to CPU cores, increase FD limits, and configure events for high concurrency.
2. TCP & HTTP Tweaks: Enable sendfile, tcp_nopush, and tcp_nodelay for low latency and efficient transfers.
3. Connection Reuse: Use keepalive_timeout and keepalive_requests to reduce overhead of repeated connections.
4. Compression: Enable gzip with balanced compression for reduced bandwidth usage.
5. Security & Limits: Hide Nginx version and set client upload limits to prevent abuse.
6. Static Content Caching: Cache static files with long expiry and disable unnecessary logging.