Ensuring Successful Data Restoration from Cassandra 3.11 to 4.0.6

Problem:

Restoring a Cassandra 3.11 snapshot to a 4.0.6 cluster using the nodetool refresh command results in an empty table, indicating a potential compatibility issue. This affects the DR environment, which needs to accurately replicate the PROD environment’s data.

Solution:

Step 1. Verify Snapshot Content:
Use nodetool listsnapshots and a test environment to ensure the snapshot contains the expected data.
Step 2. Prepare DR Cluster:
Configure the DR cluster running Cassandra 4.0.6 and ensure it is properly set up.
Step 3. Match Schema:
Align the DR environment’s schema with the PROD environment’s schema at the time of snapshot creation.
Step 4. Simulate Upgrade (if needed):
If direct restoration is not feasible, restore the snapshot to a new Cassandra 3.11 cluster, upgrade to 4.0.6, and then take a new snapshot for the DR environment.
Step 5. Restore and Verify:
Use nodetool refresh to restore the snapshot to the DR cluster and verify data presence with CQL queries.

Conclusion:

The detailed troubleshooting and step-by-step resolution ensured successful data restoration from Cassandra 3.11 to 4.0.6 by addressing compatibility and schema issues. Verifying snapshot content and simulating the upgrade process in a test environment were key to maintaining data integrity. This approach provided a reliable method for data restoration and minimized the risk of disruptions in the DR environment.