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16.4.4.4. Defining the MySQL Cluster Management Server
The [NDB_MGMD] section is used to configure
the behavior of the management server.
[MGM] can be used as an alias; the two
section names are equivalent. All parameters in the following
list are optional and assume their default values if omitted.
Note: If neither the
ExecuteOnComputer nor the
HostName parameter is present, the default
value localhost will be assumed for both.
-
Id
Each node in the cluster has a unique identity, which is
represented by an integer value in the range 1 to 63
inclusive. This ID is used by all internal cluster
messages for addressing the node.
-
ExecuteOnComputer
This refers to one of the computers defined in the
[COMPUTER] section.
-
PortNumber
This is the port number on which the management server
listens for configuration requests and management
commands.
-
LogDestination
This parameter specifies where to send cluster logging
information. There are three options in this regard:
CONSOLE, SYSLOG, and
FILE:
-
CONSOLE outputs the log to
stdout:
CONSOLE
-
SYSLOG sends the log to a
syslog facility, possible values
being one of auth,
authpriv, cron,
daemon, ftp,
kern, lpr,
mail, news,
syslog, user,
uucp, local0,
local1, local2,
local3, local4,
local5, local6,
or local7.
Note: Not every
facility is necessarily supported by every operating
system.
SYSLOG:facility=syslog
-
FILE pipes the cluster log output
to a regular file on the same machine. The following
values can be specified:
filename: The name of the
logfile.
maxsize: The maximum size (in
bytes) to which the file can grow before logging
rolls over to a new file. When this occurs, the
old logfile is renamed by appending
.N to the filename,
where N is the next
number not yet used with this name.
maxfiles: The maximum number of
logfiles.
FILE:filename=cluster.log,maxsize=1000000,maxfiles=6
It is possible to specify multiple log destinations
separated by semicolons as shown here:
CONSOLE;SYSLOG:facility=local0;FILE:filename=/var/log/mgmd
The default value for the FILE
parameter is
FILE:filename=ndb_node_id_cluster.log,maxsize=1000000,maxfiles=6,
where node_id is the ID of
the node.
-
ArbitrationRank
This parameter is used to define which nodes can act as
arbitrators. Only MGM nodes and SQL nodes can be
arbitrators. ArbitrationRank can take
one of the following values:
0: The node will never be used as
an arbitrator.
1: The node has high priority; that
is, it will be preferred as an arbitrator over
low-priority nodes.
2: Indicates a low-priority node
which be used as an arbitrator only if a node with a
higher priority is not available for that purpose.
Normally, the management server should be configured as an
arbitrator by setting its
ArbitrationRank to 1 (the default
value) and that of all SQL nodes to 0.
-
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 will be 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.)
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