Datastax CE 2.2.11集群（90节点）迁移至Apache Cassandra 2.2.11方案咨询

Hey there! I’ve worked through several migrations between DataStax Community Edition (DSE) and Apache Cassandra, especially when sticking to the exact same version (2.2.11 here). Since the versions match perfectly, this simplifies things a lot—no need to handle schema or SSTable format upgrades. Let me break down the standard, reliable methods you can use in your test environment:

Method 1: Rolling Node Replacement (Simulate Production-Grade, No Downtime) #

This approach mimics how you’d migrate a production cluster, keeping it online while swapping nodes one by one:

• Start with your existing DSE Community 2.2.11 test cluster (or replicate your production cluster’s setup in test)
• For each node you want to convert to Apache Cassandra:
  1. Decommission the node to safely move its data to other cluster members:

     nodetool decommission
     

     Wait until the command completes and nodetool status shows the node as removed.
  2. Stop the DSE service:

     sudo service dse stop
     

     (Adjust the command to match your init system—systemd, upstart, etc.)
  3. Backup critical DSE configs (e.g., /etc/dse/cassandra/cassandra.yaml, cassandra-env.sh) and data directories (optional for test, but good practice).
  4. Uninstall the DSE Community package:
     • For RPM-based systems: sudo yum remove dse-full
     • For DEB-based: sudo apt-get purge dse-full
     • For tarball installs: Just delete the DSE directory.
  5. Install Apache Cassandra 2.2.11 using your preferred method (rpm/deb/tarball)—make sure the version is an exact match.
  6. Migrate core configs from your backed-up DSE cassandra.yaml to the new Apache Cassandra config:
     • Copy over cluster_name, seeds, listen_address/broadcast_address, rpc_address/broadcast_rpc_address, data_file_directories, commitlog_directory, and endpoint_snitch.
     • Remove any DSE-specific configs (like search/graph settings)—Apache Cassandra doesn’t support these.
  7. Start the Apache Cassandra service:

     sudo service cassandra start
     

  8. Verify the node joins the cluster:

     nodetool status
     

     Wait until it shows as UN (Up/Normal).
  9. Repeat these steps for every node in the cluster.
• Pros: Tests a zero-downtime migration flow, just like production.
• Key Checks: Monitor system.log for errors, use nodetool ring to confirm data distribution stays balanced.

Method 2: Snapshot + Fresh Cluster Deployment (Fast Test Setup) #

If you just need to quickly spin up an Apache Cassandra cluster with your existing test data (no need to simulate rolling migration), this is the way to go:

1. Take a cluster-wide snapshot of all keyspaces in your DSE test cluster:

   nodetool snapshot -t migration_snapshot
   

   This creates snapshot directories under each table’s data folder (e.g., /var/lib/cassandra/data/your_keyspace/your_table-xxx/snapshots/migration_snapshot/).
2. Stop the entire DSE cluster.
3. Uninstall DSE and install Apache Cassandra 2.2.11 on all test nodes.
4. Configure the new Apache Cassandra cluster’s cassandra.yaml with the same core settings as your DSE cluster (cluster name, seeds, data directories, etc.).
5. Copy the snapshot files from each DSE node to the corresponding table directory in Apache Cassandra. For example:

   cp /var/lib/cassandra/data/your_keyspace/your_table-xxx/snapshots/migration_snapshot/* /var/lib/cassandra/data/your_keyspace/your_table-xxx/
   

   Ensure the files have the correct ownership (e.g., cassandra:cassandra).
6. Start all Apache Cassandra nodes.
7. Refresh the nodes to load the snapshot data:

   nodetool refresh
   

   Run a full repair across the cluster to ensure consistency:

   nodetool repair -full
   

• Pros: Fastest way to get an Apache Cassandra cluster with your test data.
• Key Checks: Use cqlsh to query sample data and confirm it matches the original DSE cluster.

Critical Validation Steps for Test Environment #

Don’t skip these to ensure the migration works as expected:

• Data Integrity: Compare row counts, sample records, and secondary indexes between the DSE and Apache Cassandra clusters.
• Performance Testing: Run read/write workloads that mirror your production traffic to verify performance is on par (same version should yield nearly identical results).
• Stability Monitoring: Check system.log for errors, monitor node status with nodetool status, and confirm no nodes drop offline unexpectedly.
• Tool Compatibility: If you use third-party tools (monitoring, backup, ETL), verify they work with Apache Cassandra 2.2.11.

Extra Tips #

• Since we’re on the same version, no need to run sstableupgrade—DSE Community 2.2.11 and Apache Cassandra 2.2.11 use identical SSTable formats.
• Migrate JVM settings from dse-env.sh to cassandra-env.sh (heap size, GC configuration) to keep performance consistent.
• If your DSE cluster used DSE-specific auth (like DSE Authenticator), adjust Apache Cassandra’s authenticator setting in cassandra.yaml to match (e.g., PasswordAuthenticator) and reconfigure user permissions as needed.

内容的提问来源于stack exchange，提问作者Evgeni