GlusterFS is not a two-way sync tool in the traditional sense; instead, it is a distributed file system that offers real-time replication and shared storage across multiple nodes. Here’s how it works in terms of synchronization and data management:

Key Features of GlusterFS:

1. Real-Time Replication:
   • In a GlusterFS “replicated” volume, data written to one node is automatically replicated to other nodes in real-time. This means that if a file is modified on one server, the change is immediately replicated to the other servers in the cluster.
2. Shared Storage:
   • All nodes in the cluster have access to the same data. Essentially, each node in the GlusterFS cluster serves the same data, so any change made on one node is reflected across all nodes.
3. High Availability:
   • If one server goes down, the others will still have access to the replicated data. This provides a high-availability setup where data is always available as long as one node is operational.

Is GlusterFS Two-Way Sync?

• Yes, in the sense that all nodes share the same data. Any changes made on any node are automatically replicated across the others. This means you can read/write from any server, and the changes will be reflected across the entire GlusterFS volume.
• No, in the traditional sense of syncing like rsync or Unison, which operate as file syncing tools between separate, independent systems. GlusterFS operates more like a shared storage pool where all nodes are part of a unified system, and changes propagate in real-time across the nodes.

Advantages of GlusterFS:

• Real-Time Synchronization: Changes are immediately replicated across all nodes.
• Fault Tolerance: If one node fails, the other nodes still have the same data.
• Scalability: You can easily add more nodes to scale storage capacity.

When to Use GlusterFS:

• For High Availability: If you want multiple servers to have access to the same data, and you need real-time replication with fault tolerance, GlusterFS is an excellent choice.
• For Large-Scale Environments: It’s designed for scalable environments where multiple servers need access to large datasets in a redundant, highly available manner.

When Not to Use GlusterFS:

• For Simple Syncing Between Two Servers: If you just want to sync files between two servers without setting up a full distributed file system, tools like rsync, Unison, or Syncthing might be simpler to manage.
• For Lightweight Solutions: GlusterFS requires more setup and overhead compared to simple file syncing tools.

Conclusion:

GlusterFS offers two-way synchronization in the sense that any changes made on one node are automatically reflected on all other nodes in the cluster. However, it operates as a distributed file system, not a simple file-syncing tool. If you need a robust, scalable, and highly available solution, GlusterFS can work well. But if you’re looking for a simpler two-way file sync solution, something like Unison or Syncthing might be easier to manage.