The limitations described in this section relate to functionality in the MySQL Server that is unsupported or reduced, or otherwise differs when using it with MySQL Cluster Manager.
Replication. Replication is currently not directly supported by MySQL Cluster Manager. See Section 4.3, “MySQL Cluster Manager Limitations Relating to MySQL Cluster”, for more information.
Limited mysqld option modifier support.
MySQL Cluster Manager does not recognize the
--disable prefixes for
mysqld options used as MySQL Cluster Manager configuration
attributes (for a description of these modifiers, see
Program Option Modifiers). For example, the command
set loose-skip-innodb:mysqld=true mycluster;
fails with the error No such config variable
loose-skip-innodb for process mysqld.
--skip option modifier is supported in some
but not all cases, so that commands such as
skip-innodb:mysqld=true mycluster; and
skip-grant-tables:mysqld=true mycluster; can be used
with MySQL Cluster Manager, while
mycluster; cannot. (Bug #48559, Bug #47779)
Visibility of MySQL Cluster Manager mysqld attributes and MySQL
Due in part to issues with mappings between
my.cnf option names,
mysqld command-line option names, and names
of MySQL server variables, some MySQL server variables are not
visible to MySQL Cluster Manager, or have different names. For example, the
storage_engine server variable
shown in the output of
VARIABLES in the mysql client maps
attribute used in the MySQL Cluster Manager
Dashes and underscores in MySQL option and variable names.
When using the mysql client or other MySQL
client applications, many MySQL system options and variables can
be named using either dashes or underscores in their names. For
example, you can use either
ndb-batch-size with the MySQL Server, and the
variable is set correctly. This is not the case in MySQL Cluster Manager, where
only the forms using underscores are accepted as attribute
names. For example, assuming that
is a viable cluster, the command
ndb_batch_size:mysqld=65536 mycluster; works to set
the size of ndb_batch_size on all mysqld
processes in the cluster, but
ndb-batch-size:mysqld=65536 mycluster; fails.
Dependencies between MySQL Cluster Manager mysqld attributes and
MySQL server variables.
MySQL Cluster Manager does not track dependencies between
mysqld attributes (MySQL server options and
variables). For example, MySQL Server 5.1 and earlier require,
attribute is set, that the
log_bin attribute be used as
binlog_format is used without
log_bin, mysqld fails to
start (MySQL Server Bug #42928, fixed in MySQL 5.5 and MySQL
Cluster NDB 7.2). If you do this using MySQL Cluster Manager, however, the MySQL Cluster Manager
agent reports that the operation was started successfully, and
from MySQL Cluster Manager's point of view, this is correct—MySQL Cluster Manager
started the mysqld process with the indicated
attribute settings, and it is up to the operator to verify that
the result was the one expected. In such cases, it is a good
idea to check the status of the mysqld
process, perhaps using
, before continuing.