Oracle 5.0 Reference Manual page 1577

Effective Version
MySQL 5.0.0
Restart Type: N
Each node in the cluster uses a port to connect to other nodes. By default, this port is allocated
dynamically in such a way as to ensure that no two nodes on the same host computer receive the
same port number, so it should normally not be necessary to specify a value for this parameter.
However, if you need to be able to open specific ports in a firewall to permit communication between
data nodes and API nodes (including SQL nodes), you can set this parameter to the number of
the desired port in an
section of the
default]
connections from SQL nodes, API nodes, or both.
Note
Connections from data nodes to management nodes is done using the
ndb_mgmd
see
outgoing connections to that port from any data nodes should always be
permitted.
•
NoOfReplicas
Effective Version
MySQL 5.0.0
Restart Type: IS
This global parameter can be set only in the
replicas for each table stored in the cluster. This parameter also specifies the size of node groups. A
node group is a set of nodes all storing the same information.
Node groups are formed implicitly. The first node group is formed by the set of data nodes with the
lowest node IDs, the next node group by the set of the next lowest node identities, and so on. By way
of example, assume that we have 4 data nodes and that
nodes have node IDs 2, 3, 4 and 5. Then the first node group is formed from nodes 2 and 3, and the
second node group by nodes 4 and 5. It is important to configure the cluster in such a manner that
nodes in the same node groups are not placed on the same computer because a single hardware
failure would cause the entire cluster to fail.
If no node IDs are provided, the order of the data nodes will be the determining factor for the node
group. Whether or not explicit assignments are made, they can be viewed in the output of the
management client's
There is no default value for NoOfReplicas; the recommended value is 2 for most common usage
scenarios.
The maximum possible value is 4; currently, only the values 1 and 2 are actually supported.
Important
Setting
Cluster data; in this case, the loss of a single data node causes the cluster to
fail because there are no additional copies of the data stored by that node.
MySQL Cluster Configuration Files
Type/Units
unsigned
section or (if you need to do this for multiple data nodes) the
[ndbd]
file, and then open the port having that number for incoming
config.ini
management port (the management server's PortNumber;
Section 17.3.2.4, "Defining a MySQL Cluster Management
Type/Units
integer
command.
SHOW
to 1 means that there is only a single copy of all
NoOfReplicas
1557
Default
[none]
Default
[none]
section, and defines the number of
[ndbd default]
NoOfReplicas
Range/Values
1 - 64K
[ndbd
Server") so
Range/Values
1 - 4
is set to 2. The four data