ndb_mgm supports a number of management
commands related to the cluster log. In the listing that
node_id denotes either a
database node ID or the keyword
indicates that the command should be applied to all of the
cluster's data nodes.
Turns the cluster log on.
Turns the cluster log off.
Provides information about cluster log settings.
category events with
priority less than or equal to
threshold in the cluster log.
Toggles cluster logging of events of the specified
The following table describes the default setting (for all data nodes) of the cluster log category threshold. If an event has a priority with a value lower than or equal to the priority threshold, it is reported in the cluster log.
Note that events are reported per data node, and that the threshold can be set to different values on different nodes.
|Category||Default threshold (All data nodes)|
STATISTICS category can provide a great
deal of useful data. See
Section 7.6.3, “Using
CLUSTERLOG STATISTICS in the MySQL Cluster
Management Client”, for more
Thresholds are used to filter events within each category. For
STARTUP event with a priority of 3
is not logged unless the threshold for
STARTUP is set to 3 or higher. Only events
with priority 3 or lower are sent if the threshold is 3.
The following table shows the event severity levels.
These correspond to Unix
LOG_NOTICE, which are not used or mapped.
Severity Level Value
|A condition that should be corrected immediately, such as a corrupted system database|
|Critical conditions, such as device errors or insufficient resources|
|Conditions that should be corrected, such as configuration errors|
|Conditions that are not errors, but that might require special handling|
|Debugging messages used for |
Event severity levels can be turned on or off (using
CLUSTERLOG FILTER—see above). If a
severity level is turned on, then all events with a priority
less than or equal to the category thresholds are logged. If the
severity level is turned off then no events belonging to that
severity level are logged.
Cluster log levels are set on a per
ndb_mgmd, per subscriber basis. This means
that, in a MySQL Cluster with multiple management servers,
CLUSTERLOG command in an instance
of ndb_mgm connected to one management
server affects only logs generated by that management server
but not by any of the others. This also means that, should one
of the management servers be restarted, only logs generated by
that management server are affected by the resetting of log
levels caused by the restart.