Id

Each node in the cluster has a unique identity. For a management node, this is represented by an integer value in the range 1 to 255, inclusive. This ID is used by all internal cluster messages for addressing the node, and so must be unique for each NDB Cluster node, regardless of the type of node.

The use of the Id parameter for identifying management nodes is deprecated in favor of NodeId. Although Id continues to be supported for backward compatibility, it now generates a warning and is subject to removal in a future version of NDB Cluster.

NodeId

Each node in the cluster has a unique identity. For a management node, this is represented by an integer value in the range 1 to 255 inclusive. This ID is used by all internal cluster messages for addressing the node, and so must be unique for each NDB Cluster node, regardless of the type of node.

NodeId is the preferred parameter name to use when identifying management nodes. Although the older Id continues to be supported for backward compatibility, it is now deprecated and generates a warning when used; it is also subject to removal in a future NDB Cluster release.

ExecuteOnComputer

This refers to the Id set for one of the computers defined in a [computer] section of the config.ini file.

PortNumber

This is the port number on which the management server listens for configuration requests and management commands.

The node ID for this node can be given out only to connections that explicitly request it. A management server that requests “any” node ID cannot use this one. This parameter can be used when running multiple management servers on the same host, and HostName is not sufficient for distinguishing among processes. Intended for use in testing.

HostName

Specifying this parameter defines the hostname of the computer on which the management node is to reside. To specify a hostname other than localhost, either this parameter or ExecuteOnComputer is required.

LocationDomainId

Assigns a management node to a specific availability domain (also known as an availability zone) within a cloud. By informing NDB which nodes are in which availability domains, performance can be improved in a cloud environment in the following ways:

LocationDomainId takes an integer value between 0 and 16 inclusive, with 0 being the default; using 0 is the same as leaving the parameter unset.

LogDestination

This parameter specifies where to send cluster logging information. There are three options in this regard—CONSOLE, SYSLOG, and FILE—with FILE being the default:

It is possible to specify multiple log destinations separated by semicolons as shown here:

CONSOLE;SYSLOG:facility=local0;FILE:filename=/var/log/mgmd

ArbitrationRank

This parameter is used to define which nodes can act as arbitrators. Only management nodes and SQL nodes can be arbitrators. ArbitrationRank can take one of the following values:

Normally, the management server should be configured as an arbitrator by setting its ArbitrationRank to 1 (the default for management nodes) and those for all SQL nodes to 0 (the default for SQL nodes).

You can disable arbitration completely either by setting ArbitrationRank to 0 on all management and SQL nodes, or by setting the Arbitration parameter in the [ndbd default] section of the config.ini global configuration file. Setting Arbitration causes any settings for ArbitrationRank to be disregarded.

ArbitrationDelay

An integer value which causes the management server's responses to arbitration requests to be delayed by that number of milliseconds. By default, this value is 0; it is normally not necessary to change it.

DataDir

This specifies the directory where output files from the management server are placed. These files include cluster log files, process output files, and the daemon's process ID (PID) file. (For log files, this location can be overridden by setting the FILE parameter for LogDestination, as discussed previously in this section.)

The default value for this parameter is the directory in which ndb_mgmd is located.

PortNumberStats

This parameter specifies the port number used to obtain statistical information from an NDB Cluster management server. It has no default value.

Wan

Use WAN TCP setting as default.

HeartbeatThreadPriority

Set the scheduling policy and priority of heartbeat threads for management and API nodes.

The syntax for setting this parameter is shown here:

HeartbeatThreadPriority = policy[, priority]
policy:
  {FIFO | RR}

When setting this parameter, you must specify a policy. This is one of FIFO (first in, first out) or RR (round robin). The policy value is followed optionally by the priority (an integer).

ExtraSendBufferMemory

This parameter specifies the amount of transporter send buffer memory to allocate in addition to any that has been set using TotalSendBufferMemory, SendBufferMemory, or both.

TotalSendBufferMemory

This parameter is used to determine the total amount of memory to allocate on this node for shared send buffer memory among all configured transporters.

If this parameter is set, its minimum permitted value is 256KB; 0 indicates that the parameter has not been set. For more detailed information, see Section 23.3.3.14, “Configuring NDB Cluster Send Buffer Parameters”.

HeartbeatIntervalMgmdMgmd

Specify the interval between heartbeat messages used to determine whether another management node is on contact with this one. The management node waits after 3 of these intervals to declare the connection dead; thus, the default setting of 1500 milliseconds causes the management node to wait for approximately 1600 ms before timing out.