@Rocky What's the Best Practices for blue/green deployment in shared-data arch? backup & restore or cluster snapshot?

For blue/green deployments in StarRocks Shared-data (compute-storage separation) architecture, the best practice is generally to use Cluster Snapshots (specifically metadata snapshots) rather than a traditional Backup & Restore. Here is why and how you should approach it: 1. Why Cluster Snapshots? In the shared-data architecture, all actual data is stored in remote object storage (like S3, GCS, or HDFS). The cluster's state is primarily defined by its metadata. * Speed: A cluster snapshot primarily captures the metadata. Since the data files themselves don't need to be moved or copied, creating a "Green" cluster from a snapshot is nearly instantaneous regardless of data size. * Storage Efficiency: Both the Blue and Green clusters can point to the same underlying data files in object storage initially. * Atomicity: Snapshots provide a point-in-time consistency for the entire cluster, making them ideal for testing upgrades or new configurations before cutting over traffic. 2. The Blue/Green Workflow The standard best practice for a blue/green deployment in shared-data mode involves these steps: 1. Snapshot: Take a snapshot of the existing (Blue) cluster. 2. Clone/Create Green: Deploy a new StarRocks cluster (Green) and initialize it using the metadata snapshot of the Blue cluster. 3. Validation: Run your validation suite, performance tests, or new feature checks against the Green cluster. 4. Cutover: Switch your application's connection string (or update your Load Balancer/DNS) from the Blue cluster to the Green cluster. 5. Decommission: Once the Green cluster is confirmed stable, the Blue cluster can be shut down. 3. Backup & Restore vs. Cluster Snapshot * Backup & Restore: This is typically intended for Disaster Recovery (DR) or migrating data between geographically different storage buckets. It involves exporting metadata and potentially re-indexing or verifying data integrity in a way that is much slower and more resource-intensive than a snapshot. * Cluster Snapshot: Designed for cluster cloning and rapid recovery. In a cloud-native shared-data environment, this is the native way to duplicate a cluster's state. 4. Key Considerations * Metadata Service: Ensure your metadata service (like the StarRocks FE StarOS metadata) is included in your snapshot strategy. * Write Traffic: Remember that if you continue writing to the Blue cluster after taking the snapshot, those new writes will not appear in the Green cluster. For a seamless cutover, you may need a brief "maintenance window" where you stop writes to Blue, take a final snapshot, bring up Green, and then resume writes on Green. * Object Storage Lifecycle: Be careful with data cleanup. Ensure that decommissioning the Blue cluster does not accidentally trigger a deletion of shared data files that the Green cluster is still referencing. Summary: For rapid, efficient, and reliable blue/green deployments in shared-data architecture, Cluster Snapshots are the industry-standard approach.