Upgrading Cassandra

Magic Collaboration Studio no longer supports Apache Cassandra 3.x, therefore before upgrading Magic Collaboration Studio, you need to upgrade Casandra to version 4.1.

To upgrade Cassandra

1. IMPORTANT! Flush memtables to the disk by executing the following command:

   nodetool drain

2. Shut down the Cassandra node.

3. Backup the Cassandra configuration file at: /etc/cassandra/default.conf/cassandra.yaml

4. Make a note of the existing cluster name and token count with the following command:

   grep -E 'num_tokens:|cluster_name:' cassandra.yaml

5. Uninstall/remove Cassandra 3.x (example with yum package manager)

   sudo yum remove -y cassandra

6. Install Cassandra 4.x. for installation instructions, see Installing Cassandra on Linux or Installing Cassandra on Windows.

7. Configure the 4.x node to point to the appropriate data files in the /etc/cassandra/default.conf/cassandra.yaml settings as shown in the example below.
   

   Example

   data_file_directories:
   - /data/data
   commitlog_directory: /logs/commitlog
   hints_directory: /data/hints
   saved_caches_directory: /data/saved_caches

8. Check the cluster name and token count in cassandra.yaml. If needed, replace the default values with the values set in 3.x. The example below shows the default values for a Cassandra 4.x installation. 

   Example

   cluster_name: 'Test Cluster'
   num_tokens: 16

   Cassandra 4 Configuration

   The cluster name and token count must match those values set in Cassandra 3.x.

9. Start the Cassandra 4.x node.
10. Check the log files for errors.
11. After the upgrade is complete, perform the required post-installation configuration changes. For more information, see Post-installation steps on Linux or Post-installation steps on Windows.

Additional resources

For more information about upgrading Apache Cassandra, see https://www.datastax.com/learn/whats-new-for-cassandra-4/migrating-cassandra-4x.