To support MySQL Cluster, you will need to update
my.cnf as shown in the following example.
You may also specify these parameters on the command line when
invoking the executables.
The options shown here should not be confused with those that
are used in
configuration files. Global configuration options are
discussed later in this section.
# my.cnf # example additions to my.cnf for MySQL Cluster # (valid in MySQL 5.5) # enable ndbcluster storage engine, and provide connection string for # management server host (default port is 1186) [mysqld] ndbcluster ndb-connectstring=ndb_mgmd.mysql.com # provide connection string for management server host (default port: 1186) [ndbd] connect-string=ndb_mgmd.mysql.com # provide connection string for management server host (default port: 1186) [ndb_mgm] connect-string=ndb_mgmd.mysql.com # provide location of cluster configuration file [ndb_mgmd] config-file=/etc/config.ini
(For more information on connection strings, see Section 22.214.171.124, “MySQL Cluster Connection Strings”.)
# my.cnf # example additions to my.cnf for MySQL Cluster # (will work on all versions) # enable ndbcluster storage engine, and provide connection string for management # server host to the default port 1186 [mysqld] ndbcluster ndb-connectstring=ndb_mgmd.mysql.com:1186
Once you have started a mysqld process with
ndb-connectstring parameters in the
[mysqld] in the
file as shown previously, you cannot execute any
CREATE TABLE or
ALTER TABLE statements without
having actually started the cluster. Otherwise, these
statements will fail with an error. This is by
You may also use a separate
section in the cluster
my.cnf file for
settings to be read and used by all executables:
# cluster-specific settings [mysql_cluster] ndb-connectstring=ndb_mgmd.mysql.com:1186
NDB variables that
can be set in the
my.cnf file, see
Section 126.96.36.199, “MySQL Cluster System Variables”.
The MySQL Cluster global configuration file is by convention
config.ini (but this is not
required). If needed, it is read by ndb_mgmd
at startup and can be placed in any location that can be read by
it. The location and name of the configuration are specified
with ndb_mgmd on the command line. This
option has no default value, and is ignored if
ndb_mgmd uses the configuration cache.
The global configuration file for MySQL Cluster uses INI format,
which consists of sections preceded by section headings
(surrounded by square brackets), followed by the appropriate
parameter names and values. One deviation from the standard INI
format is that the parameter name and value can be separated by
a colon (“
:”) as well as the
equal sign (“
=”); however, the
equal sign is preferred. Another deviation is that sections are
not uniquely identified by section name. Instead, unique
sections (such as two different nodes of the same type) are
identified by a unique ID specified as a parameter within the
Default values are defined for most parameters, and can also be
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
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
default] section that contains a
DataMemory line to
specify the data memory size.
In some older releases of MySQL Cluster, there was no default
always had to be specified explicitly in the
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 MySQL Cluster, and is almost certain not to be sufficient for production settings. See Section 188.8.131.52, “Recommended Starting Configuration for MySQL 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
[ndbd] sections defining these nodes.
Do not place comments on the same line as a section heading in
config.ini file; this causes the
management server not to start because it cannot parse the
configuration file in such cases.
There are six different sections that you can use in the
config.ini configuration file, as described
in the following list:
[computer]: Defines cluster hosts. This
is not required to configure a viable MySQL Cluster, but be
may used as a convenience when setting up a large cluster.
See Section 184.108.40.206, “Defining Computers in a MySQL Cluster”, for
[ndbd]: Defines a cluster data node
(ndbd process). See
Section 220.127.116.11, “Defining MySQL Cluster Data Nodes”, for
[mysqld]: Defines the cluster's MySQL
server nodes (also called SQL or API nodes). For a
discussion of SQL node configuration, see
Section 18.104.22.168, “Defining SQL and Other API Nodes in a MySQL Cluster”.
Defines a cluster management server (MGM) node. For
information concerning the configuration of management
nodes, see Section 22.214.171.124, “Defining a MySQL Cluster Management Server”.
[tcp]: Defines a TCP/IP connection
between cluster nodes, with TCP/IP being the default
connection protocol. Normally,
[tcp default] sections are not required
to set up a MySQL Cluster, as the cluster handles this
automatically; however, it may be necessary in some
situations to override the defaults provided by the cluster.
See Section 126.96.36.199, “MySQL Cluster TCP/IP Connections”, for
information about available TCP/IP configuration parameters
and how to use them. (You may also find
Section 188.8.131.52, “MySQL Cluster TCP/IP Connections Using Direct Connections” to be
of interest in some cases.)
[shm]: Defines shared-memory connections
between nodes. In MySQL 5.5, it is enabled by
default, but should still be considered experimental. For a
discussion of SHM interconnects, see
Section 184.108.40.206, “MySQL Cluster Shared-Memory Connections”.
Coherent Interface connections between cluster
data nodes. Such connections require software which, while
freely available, is not part of the MySQL Cluster
distribution, as well as specialized hardware. See
Section 220.127.116.11, “SCI Transport Connections in MySQL Cluster” for detailed
information about SCI interconnects.
You can define
default values for each
section. All Cluster parameter names are case-insensitive, which
differs from parameters specified in