Debian Context下如何优化Web服务器性能

System-Level Optimization

• Update System Regularly: Run sudo apt update && sudo apt upgrade to apply the latest performance patches and security fixes, ensuring your Debian system is up-to-date.
• Adjust Kernel Parameters: Modify /etc/sysctl.conf to optimize network and memory performance. Key parameters include:
  • net.core.somaxconn = 65535 (max TCP connections backlog)
  • net.ipv4.tcp_tw_reuse = 1 (reuse TIME-WAIT sockets)
  • vm.swappiness = 10 (reduce swap usage)
    Apply changes with sudo sysctl -p.
• Use Efficient File Systems: Format disks with XFS or Btrfs (instead of ext4) for better I/O performance, especially for high-traffic websites. XFS supports parallel I/O and is optimized for large files.
• Hardware Upgrades: Add more RAM (to reduce disk swapping), replace HDDs with SSDs (faster read/write speeds), and ensure CPU cores are sufficient for your workload (e.g., 4+ cores for moderate traffic).

Web Server Optimization (Nginx)

• Tune Worker Processes: In /etc/nginx/nginx.conf, set worker_processes auto (matches CPU cores) and worker_connections 1024 (per-worker max connections). Use epoll event model (events { use epoll; }) for efficient I/O handling.
• Enable Gzip Compression: Reduce transfer size by enabling Gzip in the HTTP block:

  gzip on;
  gzip_types text/plain text/css application/json application/javascript text/xml application/xml+rss text/javascript;
  gzip_comp_level 6;  # Balance between speed and compression
  ```.  
  

• Configure Keep-Alive: Set keepalive_timeout 65; (keep connections alive for 65 seconds) and keepalive_requests 100000 (max requests per connection) to reduce TCP handshake overhead.
• Leverage Caching: Add caching headers for static assets (images, CSS, JS) to reduce server load:

  location ~* \.(jpg|jpeg|png|gif|ico|css|js)$ {
    expires 30d;
    add_header Cache-Control "public, no-transform";
  }
  

  For dynamic content, use a reverse proxy (e.g., Nginx upstream) or a caching layer like Varnish.
• Use HTTP/2: Enable HTTP/2 in server blocks to improve page load times via multiplexing:

  listen 443 ssl http2;
  ssl_protocols TLSv1.2 TLSv1.3;
  ssl_ciphers EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH;
  ssl_prefer_server_ciphers on;
  ```.  
  
  

Web Server Optimization (Apache)

• Switch to Event MPM: Replace prefork (process-based) with event (thread-based) in /etc/apache2/mods-enabled/mpm_event.conf:

  <IfModule mpm_event_module>
    StartServers 2
    MinSpareThreads 25
    MaxSpareThreads 75
    ThreadLimit 64
    ThreadsPerChild 25
    MaxRequestWorkers 150
    MaxConnectionsPerChild 0
  </IfModule>
  

  Disable unused modules (e.g., mod_status, mod_info) to reduce memory usage.
• Enable mod_cache: Configure disk caching for static content in /etc/apache2/mods-enabled/cache_disk.conf:

  <IfModule mod_cache_disk.c>
    CacheRoot /var/cache/apache2/mod_cache_disk
    CacheEnable disk /
    CacheDirLevels 2
    CacheDirLength 1
  </IfModule>
  ```.  
  

• Disable .htaccess: Prevent Apache from reading .htaccess files (in virtual host configs) to improve performance:

  <Directory /var/www/html>
    AllowOverride None
  </Directory>
  ```.  
  
  

Database Optimization (MySQL/MariaDB)

• Tune InnoDB Buffer Pool: In /etc/mysql/mysql.conf.d/mysqld.cnf, set innodb_buffer_pool_size to 70-80% of available RAM (e.g., innodb_buffer_pool_size = 1G for 1.5GB RAM) to cache table data.
• Optimize Queries: Use tools like mysqlslowquery.log (enable with slow_query_log = 1 and long_query_time = 2) to identify and optimize slow queries. Add indexes to frequently queried columns.
• Adjust Connection Limits: Set max_connections based on your workload (e.g., max_connections = 50) and use pm.max_children in PHP-FPM to match (see PHP optimization below).

PHP Optimization

• Enable OPcache: In /etc/php/7.x/fpm/php.ini (adjust version as needed), enable OPcache to cache compiled PHP scripts:

  opcache.enable = 1
  opcache.memory_consumption = 256
  opcache.max_accelerated_files = 10000
  opcache.interned_strings_buffer = 64
  opcache.fast_shutdown = 1
  

  Restart PHP-FPM (sudo systemctl restart php7.x-fpm) after changes.
• Tune PHP-FPM Pools: In /etc/php/7.x/fpm/pool.d/www.conf, adjust:
  • pm = dynamic (better resource management)
  • pm.max_children = 50 (max child processes)
  • pm.start_servers = 5 (startup servers)
  • pm.min_spare_servers = 5 (min idle servers)
  • pm.max_spare_servers = 35 (max idle servers).

Monitoring and Maintenance

• Use Monitoring Tools: Install htop (process monitoring), netdata (real-time metrics), or Prometheus + Grafana (advanced dashboards) to track CPU, memory, disk I/O, and network usage.
• Analyze Logs: Regularly review Nginx/Apache access/error logs (e.g., tail -f /var/log/nginx/access.log) and MySQL slow query logs to identify bottlenecks (e.g., high 404 errors, slow queries).
• Clean Up Regularly: Remove unused packages (sudo apt autoremove), clear package caches (sudo apt clean), and delete old log files (logrotate or manual deletion) to free up disk space.