How to perform Nginx performance tuning? What are the key parameters?

Nginx performance tuning is a systematic engineering task that requires optimization from multiple dimensions. Proper configuration can significantly improve Nginx's processing capability and response speed.

Core Configuration Optimization:

nginx
# Global configuration
user nginx;
worker_processes auto;  # Automatically set to CPU core count
worker_rlimit_nofile 100000;  # File descriptor limit
worker_cpu_affinity auto;  # CPU affinity binding

events {
    worker_connections 65535;  # Maximum connections per worker
    use epoll;  # Use epoll on Linux
    multi_accept on;  # Accept multiple connections simultaneously
    accept_mutex off;  # Disable mutex lock to reduce lock contention
}

http {
    # Basic optimization
    sendfile on;  # Enable efficient file transfer
    tcp_nopush on;  # Optimize packet sending
    tcp_nodelay on;  # Disable Nagle's algorithm
    keepalive_timeout 65;  # Keep-alive timeout
    keepalive_requests 100;  # Maximum requests per keep-alive connection
    
    # Buffer optimization
    client_body_buffer_size 128k;  # Client request body buffer
    client_max_body_size 10m;  # Maximum request body size
    client_header_buffer_size 1k;  # Client request header buffer
    large_client_header_buffers 4 4k;  # Large request header buffer
    
    # Output buffering
    output_buffers 1 32k;  # Output buffer
    postpone_output 1460;  # Delay output
    
    # File cache
    open_file_cache max=100000 inactive=20s;  # File descriptor cache
    open_file_cache_valid 30s;  # Cache validation interval
    open_file_cache_min_uses 2;  # Minimum usage count
    open_file_cache_errors on;  # Cache error information
    
    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript application/json application/javascript application/xml+rss;
    gzip_disable "msie6";
}

Worker Process Optimization:

nginx
# Set based on CPU core count
worker_processes auto;

# Bind CPU cores (manual setting)
# Assuming 4-core CPU
worker_processes 4;
worker_cpu_affinity 0001 0010 0100 1000;

# Set worker process priority
worker_priority -5;  # -20 to 19, lower value means higher priority

Connection Optimization:

nginx
events {
    # Increase connection count
    worker_connections 65535;
    
    # Accept multiple connections simultaneously
    multi_accept on;
    
    # Disable mutex lock (for high concurrency)
    accept_mutex off;
    
    # Use efficient event model
    use epoll;  # Linux
    # use kqueue;  # BSD/macOS
}

http {
    # Keep-alive optimization
    keepalive_timeout 65;
    keepalive_requests 100;
    
    # Upstream server keep-alive
    upstream backend {
        server 192.168.1.100:8080;
        keepalive 32;  # Keep 32 idle connections
    }
    
    # Proxy timeout settings
    proxy_connect_timeout 60s;
    proxy_send_timeout 60s;
    proxy_read_timeout 60s;
}

Buffer Optimization:

nginx
http {
    # Client buffers
    client_body_buffer_size 128k;
    client_max_body_size 10m;
    client_header_buffer_size 1k;
    large_client_header_buffers 4 4k;
    
    # Proxy buffers
    proxy_buffering on;
    proxy_buffer_size 4k;
    proxy_buffers 8 4k;
    proxy_busy_buffers_size 8k;
    
    # FastCGI buffers
    fastcgi_buffer_size 4k;
    fastcgi_buffers 8 4k;
    
    # Output buffers
    output_buffers 1 32k;
    postpone_output 1460;
}

File Operation Optimization:

nginx
http {
    # File cache
    open_file_cache max=100000 inactive=20s;
    open_file_cache_valid 30s;
    open_file_cache_min_uses 2;
    open_file_cache_errors on;
    
    # Efficient file transfer
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    
    # Direct I/O (for large files)
    # directio 4m;
}

Compression Optimization:

nginx
http {
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;  # Minimum file size to compress
    gzip_comp_level 6;  # Compression level 1-9
    gzip_buffers 16 8k;  # Compression buffers
    gzip_http_version 1.1;
    gzip_types text/plain text/css text/xml text/javascript 
               application/json application/javascript 
               application/xml+rss application/rss+xml 
               application/atom+xml image/svg+xml;
    gzip_disable "msie6";
    
    # Static resource pre-compression
    gzip_static on;
}

Log Optimization:

nginx
http {
    # Custom log format
    log_format main '$remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent" '
                    'rt=$request_time uct="$upstream_connect_time" '
                    'uht="$upstream_header_time" urt="$upstream_response_time"';
    
    # Access log
    access_log /var/log/nginx/access.log main buffer=32k flush=5s;
    
    # Error log
    error_log /var/log/nginx/error.log warn;
    
    # Disable static resource logging
    location ~* \.(css|js|jpg|jpeg|png|gif|ico|svg|woff|woff2)$ {
        access_log off;
    }
}

SSL/TLS Optimization:

nginx
server {
    listen 443 ssl http2;
    
    # SSL session cache
    ssl_session_cache shared:SSL:50m;
    ssl_session_timeout 1d;
    ssl_session_tickets off;
    
    # SSL buffers
    ssl_buffer_size 4k;
    
    # Protocols and cipher suites
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;
    ssl_prefer_server_ciphers on;
    
    # OCSP Stapling
    ssl_stapling on;
    ssl_stapling_verify on;
}

System-Level Optimization:

bash
# /etc/sysctl.conf
# File descriptors
fs.file-max = 1000000

# TCP parameters
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 65536 4194304
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_tw_reuse = 1

# Apply configuration
sysctl -p

User Limits:

bash
# /etc/security/limits.conf
nginx soft nofile 65535
nginx hard nofile 65535

Monitoring and Diagnostics:

nginx
# Status monitoring
location /nginx_status {
    stub_status on;
    access_log off;
    allow 127.0.0.1;
    deny all;
}

# Request tracing
location /debug {
    add_header X-Request-ID $request_id;
    add_header X-Upstream-Addr $upstream_addr;
}

Performance Testing Tools:

bash
# wrk stress test
wrk -t12 -c4000 -d30s http://example.com/

# ab stress test
ab -n 10000 -c 1000 http://example.com/

# siege stress test
siege -c 100 -t 60S http://example.com/

Key Performance Metrics:

QPS (Queries Per Second): Measure processing capability
Response Time: Average, P95, P99
Concurrent Connections: Current active connections
Error Rate: Ratio of 4xx, 5xx errors
CPU Usage: Should not consistently exceed 70%
Memory Usage: Monitor memory consumption
Disk I/O: Monitor read/write performance

Tuning Recommendations:

Gradual tuning: Adjust only one parameter at a time, observe results
Benchmarking: Perform performance comparison before and after tuning
Monitor metrics: Continuously monitor key performance indicators
Log analysis: Analyze access logs to identify bottlenecks
Regular review: Periodically check if configuration is reasonable