MySQL Cluster Manager 8.0 User Manual  /  MySQL Cluster Manager Limitations and Known Issues  /  MySQL Cluster Manager Usage and Design Limitations

6.1 MySQL Cluster Manager Usage and Design Limitations

The limitations discussed in this section occur by intention or design in MySQL Cluster Manager 8.0.27. Some of these items may become obsolete in future versions; we will update this section accordingly if and as those changes come about.

change process command.  Currently, the change process command can be used only to exchange an ndbd process for an ndbmtd process, or the reverse. That is, in effect, it can be used only to switch a data node between a single-threaded process and a multithreaded process. It cannot be used for changing a cluster node's type (for example, you cannot change a data node to an SQL node, management node, or NDB API application node).

Concurrent client sessions.  Currently there is no negotiation or arbitration between multiple mcm clients. While it is possible to use the client from multiple locations, you should be careful always to allow a reconfiguration command issued in one mcm client session to finish executing before issuing a new command in a different client session. The same must be ensured when using the -B or --background option to regain control before completion; see Backgrounded commands and error handling.

IPv6 and host names (Windows).  When IPv6 support is enabled on Windows systems, host names other than localhost are resolved using IPv6. When an IPv6-enabled Windows system is used as a MySQL NDB Cluster host under MySQL Cluster Manager, you must reference it using its IPv4 address. Otherwise, mcm will be unable to connect to the agent process on that host.

This applies to host names used with the MySQL Cluster Manager client commands create cluster, create site, add hosts, add package, delete package, stop agents, and add process.

Use of antivirus software on Windows platforms.  On-access scanning by antivirus software on Windows platforms might cause access to the cluster configuration file being denied for the mcmd agent, causing updates for the cluster configuration to fail sometimes.