NDB Cluster Configuration Files Default values are defined for most parameters, and can also be specified in  config.ini . To create a default value section, simply add the word  default  to the section name. For example, an  [ndbd]  section contains parameters that apply to a particular data node, whereas an  [ndbd default]  section contains parameters that apply to all data nodes. Suppose that all data nodes should use the same data memory size. To configure them all, create an  [ndbd default]  section that contains a  DataMemory  line to specify the data memory size. If used, the  [ndbd default]  section must precede any  [ndbd]  sections in the configuration file. This is also true for  default  sections of any other type. In some older releases of NDB Cluster, there was no default value for NoOfReplicas , which always had to be specified explicitly in the  [ndbd default]  section. Although this parameter now has a default value of 2, which is the recommended setting in most common usage scenarios, it is still recommended practice to set this parameter explicitly. The global configuration file must define the computers and nodes involved in the cluster and on which computers these nodes are located. An example of a simple configuration file for a cluster consisting of one management server, two data nodes and two MySQL servers is shown here: # file "config.ini" - 2 data nodes and 2 SQL nodes # This file is placed in the startup directory of ndb_mgmd (the # management server) # The first MySQL Server can be started from any host. The second # can be started only on the host mysqld_5.mysql.com [ndbd default] NoOfReplicas= 2 DataDir= /var/lib/mysql-cluster [ndb_mgmd] Hostname= ndb_mgmd.mysql.com DataDir= /var/lib/mysql-cluster [ndbd] HostName= ndbd_2.mysql.com [ndbd] HostName= ndbd_3.mysql.com [mysqld] [mysqld] HostName= mysqld_5.mysql.com The preceding example is intended as a minimal starting configuration for purposes of familiarization with NDB Cluster , and is almost certain not to be sufficient for production settings. See Section 23.3.3.2, “Recommended Starting Configuration for NDB Cluster” , which provides a more complete example starting configuration. Each node has its own section in the  config.ini  file. For example, this cluster has two data nodes, so the preceding configuration file contains two  [ndbd]  sections defining these nodes. Do not place comments on the same line as a section heading in the  config.ini file; this causes the management server not to start because it cannot parse the configuration file in such cases. Note Note 4055 Note