寻求开源自建CDN方案：专属服务器负载不足，需扩容同步节点

Great question—this is a super common scenario when scaling static video content without the overhead of a full multi-region CDN. Let’s break down the best open-source solutions tailored exactly to your needs:

1. Lightweight Sync + Load Balancer (Best for Quick Setup) #

This approach keeps your existing source server intact, syncs files to new servers, and uses a load balancer to distribute traffic across all nodes. Perfect if you don’t want to overhaul your storage setup.

a. Lsyncd (Real-Time File Sync) #

Lsyncd is a lightweight daemon that monitors file system changes and uses rsync under the hood to sync updates to your new servers. It’s ideal for large video files because it supports incremental syncs (only sends changed parts of files) and minimizes bandwidth usage.

Setup Steps:

• Install Lsyncd on your source server (most distros have packages: apt install lsyncd or yum install lsyncd).
• First, run a one-time full sync to seed your new servers:

  rsync -avz --progress /path/to/your/5TB/videos user@new-server-ip:/path/to/target/directory
  

• Create a Lsyncd config file (e.g., /etc/lsyncd/lsyncd.conf.lua) to handle real-time syncs:

  settings {
      logfile = "/var/log/lsyncd/lsyncd.log",
      statusFile = "/var/log/lsyncd/lsyncd.status",
      inotifyMode = "CloseWrite",  # Only sync when files are fully written
      maxProcesses = 4,  # Adjust based on your server’s capacity
  }
  
  sync {
      default.rsync,
      source = "/path/to/your/5TB/videos",
      target = "user@new-server-1:/path/to/target/directory",
      rsync = {
          archive = true,
          compress = true,
          verbose = false,
          rsh = "/usr/bin/ssh -i /root/.ssh/id_rsa"  # Use SSH keys for passwordless sync
      }
  }
  # Repeat the sync block for each new server you add
  

• Start the Lsyncd service: systemctl start lsyncd && systemctl enable lsyncd

b. Rsync + Cron (Scheduled Sync) #

If your video content doesn’t update frequently (e.g., once a day/week), skip the daemon and use a cron job to run periodic rsync syncs. This is even simpler and has zero ongoing resource overhead.

Setup Example:

• Add a cron job on your source server (run crontab -e):

  # Sync to new server every night at 2 AM
  0 2 * * * rsync -avz --delete /path/to/your/videos user@new-server-ip:/path/to/target/directory > /var/log/rsync_sync.log 2>&1
  

• The --delete flag ensures deleted files on the source are removed from the sync servers (optional, depending on your needs).

c. Load Balancer (Nginx or HAProxy) #

Once your servers are synced, use an open-source load balancer to distribute user traffic across all nodes. Nginx is the most popular choice for static content:

Nginx Load Balancer Config:

http {
    upstream video_cluster {
        server source-server-ip:80;
        server new-server-1-ip:80;
        server new-server-2-ip:80;
        # Add weight if some servers are more powerful: server source-server-ip:80 weight=2;
    }

    server {
        listen 80;
        server_name your-video-domain.com;

        location /videos {
            proxy_pass http://video_cluster;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            # Enable caching for static videos (optional but recommended)
            proxy_cache_valid 200 7d;
        }
    }
}

2. Distributed File System (Best for Long-Term Scalability) #

If you plan to add more servers down the line, a distributed file system will let you pool storage across all nodes and automatically sync files without separate sync tools.

GlusterFS #

GlusterFS is a scalable, open-source distributed file system that turns multiple servers into a single unified storage volume. All nodes will have access to the same video files, and you can add more servers to the cluster as needed.

Key Benefits:

• Automatic file replication across nodes (so if one server goes down, others still have the files)
• No need for separate sync tools—files are available on all nodes instantly
• Supports large files (perfect for 5TB of videos)

Quick Setup:

1. Install GlusterFS on all servers.
2. Create a trusted storage pool with all your servers.
3. Create a replicated volume (e.g., 3-way replication for redundancy).
4. Mount the volume on each server’s web root (e.g., /var/www/videos).
5. Point each server’s Nginx to the mounted volume, then use the same Nginx load balancer setup above to distribute traffic.

3. Honorable Mention: MinIO (Distributed Object Storage) #

If you want to shift to object storage (great for large media files), MinIO is an open-source S3-compatible object store. You can set up a MinIO cluster across your servers, upload your videos to the cluster, and all nodes will serve the content. It’s easy to scale and integrates well with Nginx for load balancing.

内容的提问来源于stack exchange，提问作者Zakaria Abdelaziz