16.5.3. ndb_mgmd, the Management Server Process
The management server is the process that reads the cluster
configuration file and distributes this information to all nodes
in the cluster that request it. It also maintains a log of
cluster activities. Management clients can connect to the
management server and check the cluster's status.
It is not strictly necessary to specify a connectstring when
starting the management server. However, if you are using more
than one management server, a connectstring should be provided
and each node in the cluster should specify its node ID
explicitly.
See Section 16.4.4.2, “The MySQL Cluster connectstring”, for
information about using connectstrings.
Section 16.5.5, “Command Options for MySQL Cluster Processes”, describes other
options for ndb_mgmd.
The following files are created or used by
ndb_mgmd in its starting directory, and are
placed in the DataDir as specified in the
config.ini configuration file. In the list
that follows, node_id is the unique
node identifier.
config.ini is the configuration file
for the cluster as a whole. This file is created by the user
and read by the management server.
Section 16.4, “MySQL Cluster Configuration”, discusses how
to set up this file.
-
ndb_node_id_cluster.log
is the cluster events log file. Examples of such events
include checkpoint startup and completion, node startup
events, node failures, and levels of memory usage. A
complete listing of cluster events with descriptions may be
found in Section 16.6, “Management of MySQL Cluster”.
When the size of the cluster log reaches one million bytes,
the file is renamed to
ndb_node_id_cluster.log.seq_id,
where seq_id is the sequence
number of the cluster log file. (For example: If files with
the sequence numbers 1, 2, and 3 already exist, the next log
file is named using the number 4.)
ndb_node_id_out.log
is the file used for stdout and
stderr when running the management server
as a daemon.
ndb_node_id.pid
is the process ID file used when running the management
server as a daemon.
