MySQL 8.0 FAQ: NDB Cluster and Section 23.2.8, “The NDB Cluster Auto-Installer (No longer supported)” , for more information about these tools. The data that was held in memory by the cluster’s data nodes is written to disk, and is reloaded into memory the next time that the cluster is started. It can be helpful as a fail-safe. Only one management node controls the cluster at any given time, but it is possible to configure one management node as primary, and one or more additional management nodes to take over in the event that the primary management node fails. See Section 23.3.3, “NDB Cluster Configuration Files” , for information on how to configure NDB Cluster management nodes. Yes, as long as all machines and operating systems have the same “endianness”  (all big-endian or all little-endian). It is also possible to use software from different NDB Cluster releases on different nodes. However, we support such use only as part of a rolling upgrade procedure (see Section 23.5.5, “Performing a Rolling Restart of an NDB Cluster” ). Yes, it is possible to do this. In the case of multiple data nodes, it is advisable (but not required) for each node to use a different data directory. If you want to run multiple SQL nodes on one machine, each instance of  mysqld  must use a different TCP/IP port. Running data nodes and SQL nodes together on the same host is possible, but you should be aware that the  ndbd  or  ndbmtd  processes may compete for memory with  mysqld . Yes, it is possible to use DNS and DHCP for cluster hosts. However, if your application requires “five nines”  availability, you should use fixed (numeric) IP addresses, since making communication between Cluster hosts dependent on services such as DNS and DHCP introduces additional potential points of failure. IPv6 is supported for connections between SQL nodes (MySQL servers), but connections between all other types of NDB Cluster nodes must use IPv4. In practical terms, this means that you can use IPv6 for replication between NDB Clusters, but connections between nodes in the same NDB Cluster must use IPv4. For more information, see Section 23.6.3, “Known Issues in NDB Cluster Replication” . MySQL user accounts and privileges are normally not automatically propagated between different MySQL servers accessing the same NDB Cluster. MySQL NDB Cluster provides support for shared and synchronized users and privileges using the  NDB_STORED_USER  privilege; see Section 23.5.12, “Distributed MySQL Privileges with NDB_STORED_USER” , for more information. You should be aware that this implementation is new to NDB 8.0 and is not compatible with the shared privileges mechanism employed in earlier versions of NDB Cluster, which is no longer supported in NDB 8.0. 5256 A.10.32. What happens to NDB Cluster data when the NDB Cluster is shut down? A.10.33. Is it a good idea to have more than one management node for an NDB Cluster? A.10.34. Can I mix different kinds of hardware and operating systems in one NDB Cluster? A.10.35. Can I run two data nodes on a single host? Two SQL nodes? A.10.36. Can I use host names with NDB Cluster? A.10.37. Does NDB Cluster support IPv6? A.10.38. How do I handle MySQL users in an NDB Cluster having multiple MySQL servers?