6.3 MySQL Cluster Manager Limitations Relating to MySQL NDB Cluster

This section describes limitations relating to MySQL NDB Cluster functionality that is unsupported or curtailed by MySQL Cluster Manager 8.4.

MySQL Cluster Manager and replication. MySQL Cluster Manager currently does not provide any explicit support for MySQL NDB Cluster Replication. However, you should still be able to perform manual setup of replication of a MySQL NDB Cluster that is managed by MySQL Cluster Manager.

Backup and restore operations. MySQL Cluster Manager provides integrated backup and restore functionality. You can back up NDB databases and tables using the mcm client backup cluster command, and restore them using the restore cluster client command. MySQL Cluster Manager also supports restoration of distributed privileges.

You can also back up NDB databases and tables using the ndb_mgm client START BACKUP command, and restore them using the ndb_restore program; however MySQL Cluster Manager is not aware of backups that it was not employed to create. Both of the programs just mentioned are supplied with the MySQL NDB Cluster distribution.

Note

Backups of tables using storage engines other than NDB, as well as of all other database objects that are not tables, cannot be made using MySQL Cluster Manager, and must be made using some other method, such as mysqldump.

Rolling restarts. Currently, all cluster nodes must be running in order to perform a rolling restart using MySQL Cluster Manager. However, MySQL NDB Cluster itself requires only that at least one management server and all data nodes are running (in other words, any mysqld processes and any additional ndb_mgmd processes can be stopped). In such cases, you can perform the rolling restart manually, after stopping the MySQL Cluster Manager agent.

When making changes in configuration attributes only those nodes requiring a restart to make the change take effect are actually restarted. ndbapi nodes are never restarted by MySQL Cluster Manager.

Cluster Imports. MySQL Cluster Manager will reject an import if it cannot access the process information of the cluster being imported. Therefore, the MySQL Cluster Manager agents must be run by a sufficiently privileged user—normally the same user that runs the cluster.

Cluster Reconfiguration. Cluster configuration updates (using the set or reset command) that would trigger a rolling restart of the nodes are not executed by MySQL Cluster Manager unless there are more than one data node defined for each node group; to perform such updates when the requirement is not met, a user should, using MySQL Cluster Manager, stop the cluster, use the set or reset command to change the cluster configurations, and then start the cluster again. If, however, your configuration changes require an initial restart of your cluster, you will need to backup the data, recreate your cluster form scratch with the new settings, and then restore your old data onto it.