{"id":2981,"date":"2025-12-29T16:22:25","date_gmt":"2025-12-29T08:22:25","guid":{"rendered":"https:\/\/www.ruianding.com\/blog\/?p=2981"},"modified":"2026-02-07T15:10:28","modified_gmt":"2026-02-07T07:10:28","slug":"migration-memo-scaling-a-web-architecture-across-cloud-providers","status":"publish","type":"post","link":"https:\/\/www.ruianding.com\/blog\/migration-memo-scaling-a-web-architecture-across-cloud-providers\/","title":{"rendered":"Migration Memo: The Ultimate Pitfall Guide & Best Practices"},"content":{"rendered":"\n

Overview<\/h2>\n\n\n\n

This guide documents the high-stakes migration of a multi-service web ecosystem (WordPress, ComfyUI, Dify, GPT, etc.) from Server A<\/strong> to Server B<\/strong>. Our goal was to achieve a seamless transition of dozens of subdomains while maintaining SSL integrity and remote database connectivity.<\/p>\n\n\n\n

Phase 1: The “Connectivity” Layer & Corporate Firewalls<\/h2>\n\n\n\n

Before moving data, we addressed the “SMB Trap.”<\/p>\n\n\n\n

    \n
  • The Issue:<\/strong> Port 445 (SMB) was blocked by corporate DPI (Deep Packet Inspection) for international traffic.<\/li>\n\n\n\n
  • The Lesson:<\/strong> Never rely on raw sensitive protocols over public IPs.<\/li>\n\n\n\n
  • Resolution:<\/strong> Encapsulate traffic using Tailscale<\/strong> or SSH Tunneling<\/strong> to bypass inspection.<\/li>\n<\/ul>\n\n\n\n

    <\/p>\n\n\n\n

    Phase 2: File Transfer & Directory Traps<\/h2>\n\n\n\n

    During the move, two common Linux file-handling errors occurred:<\/p>\n\n\n\n

      \n
    1. The SCP “Fake File” Trap:<\/strong> If the target directory doesn’t exist, SCP saves the upload as a file<\/em> with that name instead of a folder.<\/li>\n\n\n\n
    2. The Tar “Nested Doll” Effect:<\/strong> Extracting a package into a pre-made folder often creates redundant layers (e.g., \/data\/site\/site\/<\/code>).<\/li>\n<\/ol>\n\n\n\n

      The Recovery Fix:<\/strong><\/p>\n\n\n\n

      # Rename the \"fake\" file back to archive\nmv \/data \/data_backup.tar.gz\n\n# Create correct target\nmkdir -p \/data\/ruianding.com\n\n# Flatten\ntar -xzvf \/data_backup.tar.gz -C \/data\/ruianding.com --strip-components=1 \n<\/pre>\n\n\n\n
      Phase 3: Apache Mass Migration<\/h2>\n\n\n\n
      With over 10 subdomains, manual configuration is a recipe for disaster. We used Environment Mirroring<\/strong>.<\/p>\n\n\n\n
      1. Packaging Everything (Server A)<\/h3>\n\n\n\n
      Follow symbolic links with -h<\/code> to ensure SSL certificates are actually included, not just the links.<\/p>\n\n\n\n
      cd \/etc\/apache2\nsudo tar -czvf sites_backup.tar.gz sites-available\/\nsudo tar -chzvf letsencrypt_all.tar.gz \/etc\/letsencrypt\/\n<\/pre>\n\n\n\n
      2. Environment Mirroring (Server B)<\/h3>\n\n\n\n
      # Install environment\nsudo apt update && sudo apt install apache2 certbot php-mysql -y\n\n# Enable Proxy & SSL modules\nsudo a2enmod proxy proxy_http proxy_balancer lbmethod_byrequests ssl rewrite headers\n\n# Batch enable sites\ncd \/etc\/apache2\/sites-available\nls *.conf | xargs -i sudo a2ensite {}\n\nsudo systemctl restart apache2\n<\/pre>\n\n\n\n
      <\/p>\n\n\n\n
      Phase 4: The MySQL 8.0 & Latency “Reality Check”<\/h2>\n\n\n\n
      1. The Syntax Barrier (MySQL 8.0+)<\/h3>\n\n\n\n
      Pitfall: <\/strong>GRANT … IDENTIFIED BY is deprecated and throws Error 1064.<\/p>\n\n\n\n
      Lesson: <\/strong>Identity and Authorization are now separate.<\/p>\n\n\n\n
      -- On Server A\n\nCREATE USER 'user_id'@'Server_B_IP' IDENTIFIED BY 'your_actual_password';\nGRANT ALL PRIVILEGES ON database.* TO 'user_id'@'Server_B_IP';\nFLUSH PRIVILEGES;\n<\/pre>\n\n\n\n
      2. The Hostfile Hack<\/h3>\n\n\n\n
      To decouple code from infrastructure, we mapped the DB host at the OS level on Server B:<\/p>\n\n\n\n
      # \/etc\/hosts\n[Server_A_IP]  mysql_remote_host\n\n# wp-config.php\ndefine( 'DB_HOST', 'mysql_remote_host' );\n<\/pre>\n\n\n\n
      3. The “Latency Tax” <\/h3>\n\n\n\n
      We initially attempted a distributed setup: the Database<\/strong> remained on Server A (Japan), while the WordPress Code<\/strong> lived on Server B (China).<\/p>\n\n\n\n
      The Observation:<\/strong> The website became extremely sluggish, often taking 5\u201310 seconds just to render a basic page.<\/p>\n\n\n\n
      The “Chatty” Reality:<\/strong> WordPress is a “chatty” application. To load a single page, it doesn’t just ask the database once; it sends dozens of small queries to fetch options, metadata, and content.<\/p>\n\n\n\n
      The Math:<\/strong><\/p>\n\n\n\n
        \n
      • Single Query Latency (RTT):<\/strong> ~60ms (China to Japan)<\/li>\n\n\n\n
      • WordPress Page Load:<\/strong> ~80 SQL queries<\/li>\n\n\n\n
      • Total Wait Time:<\/strong> 80 * 60 ms = 4,800 ms = 4.8 seconds<\/strong> of pure silence while the server waits for data to cross the ocean.<\/li>\n<\/ul>\n\n\n\n
        The Verdict:<\/strong> Database proximity is non-negotiable for monolithic apps like WordPress. In a cross-border setup, the “Latency Tax” is too high to pay. Moving the database to the same local network as the code is the only way to achieve sub-second load times.<\/p>\n\n\n\n
        <\/p>\n","protected":false},"excerpt":{"rendered":"
        Overview This guide documents the high-stakes migration of a multi-service web ecosystem (WordPress, ComfyUI, Dify, GPT, etc.) from Server A to Server B. Our goal was to achieve a seamless transition of dozens of subdomains while maintaining SSL integrity and remote database connectivity. Phase 1: The “Connectivity” Layer & Corporate Firewalls Before moving data, we […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_themeisle_gutenberg_block_has_review":false,"footnotes":""},"categories":[51,76,10],"tags":[71,59,78,44],"class_list":["post-2981","post","type-post","status-publish","format-standard","hentry","category-mysql","category-network","category-tutorial","tag-apache","tag-migration","tag-mysql","tag-network"],"yoast_head":"\nMigration Memo: The Ultimate Pitfall Guide & Best Practices - \u6781\u7b80IT\uff5cSimpleIT<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ruianding.com\/blog\/migration-memo-scaling-a-web-architecture-across-cloud-providers\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Migration Memo: The Ultimate Pitfall Guide & Best Practices - \u6781\u7b80IT\uff5cSimpleIT\" \/>\n<meta property=\"og:description\" content=\"Overview This guide documents the high-stakes migration of a multi-service web ecosystem (WordPress, ComfyUI, Dify, GPT, etc.) from Server A to Server B. 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