This chapter contains information about MySQL Cluster, which is a high-availability, high-redundancy version of MySQL adapted for the distributed computing environment. Recent releases of MySQL Cluster use version 7 of the NDBCLUSTER storage engine (also known as NDB) to enable running several computers with MySQL servers and other software in a cluster; the latest releases available for production use incorporate NDB version 7.3.

Support for the NDBCLUSTER storage engine is not included in standard MySQL Server 5.6 binaries built by Oracle. Instead, users of MySQL Cluster binaries from Oracle should upgrade to the most recent binary release of MySQL Cluster for supported platforms—these include RPMs that should work with most Linux distributions. MySQL Cluster users who build from source should use the sources provided for MySQL Cluster. (Locations where the sources can be obtained are listed later in this section.)

This chapter contains information about MySQL Cluster NDB 7.3 releases through 5.6.11-ndb-7.3.3. Currently, the MySQL Cluster NDB 7.3 release series is Generally Available (GA), as is MySQL Cluster NDB 7.2. MySQL Cluster NDB 7.1 and MySQL Cluster NDB 7.0 are previous GA release series; although they are still supported, we recommend that new deployments use MySQL Cluster NDB 7.3. For information about MySQL Cluster NDB 7.2, see MySQL Cluster NDB 7.2; for information about MySQL Cluster NDB 7.1, and previous versions of MySQL Cluster, see MySQL Cluster NDB 6.1 - 7.1.

Supported Platforms. MySQL Cluster is currently available and supported on a number of platforms. For exact levels of support available for on specific combinations of operating system versions, operating system distributions, and hardware platforms, please refer to http://www.mysql.com/support/supportedplatforms/cluster.html.

Availability. MySQL Cluster binary and source packages are available for supported platforms from http://dev.mysql.com/downloads/cluster/.

MySQL Cluster release numbers. MySQL Cluster follows a somewhat different release pattern from the mainline MySQL Server 5.6 series of releases. In this Manual and other MySQL documentation, we identify these and later MySQL Cluster releases employing a version number that begins with "NDB". This version number is that of the NDBCLUSTER storage engine used in the release, and not of the MySQL server version on which the MySQL Cluster release is based.

Version strings used in MySQL Cluster software. The version string displayed by MySQL Cluster programs uses this format:

mysql-mysql_server_version-ndb-ndb_engine_version

mysql_server_version represents the version of the MySQL Server on which the MySQL Cluster release is based. For all MySQL Cluster NDB 7.3 releases, this is "5.6". ndb_engine_version is the version of the NDB storage engine used by this release of the MySQL Cluster software. You can see this format used in the mysql client, as shown here:

shell> mysqlWelcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 2Server version: 5.6.11-ndb-7.3.3 Source distributionType 'help;' or '\h' for help. Type '\c' to clear the buffer.mysql> SELECT VERSION()\G*************************** 1. row ***************************VERSION(): 5.6.11-ndb-7.3.31 row in set (0.00 sec)

This version string is also displayed in the output of the SHOW command in the ndb_mgm client:

ndb_mgm> SHOWConnected to Management Server at: localhost:1186Cluster Configuration---------------------[ndbd(NDB)]     2 node(s)id=1    @10.0.10.6  (5.6.11-ndb-7.3.3, Nodegroup: 0, Master)id=2    @10.0.10.8  (5.6.11-ndb-7.3.3, Nodegroup: 0)[ndb_mgmd(MGM)] 1 node(s)id=3    @10.0.10.2  (5.6.11-ndb-7.3.3)[mysqld(API)]   2 node(s)id=4    @10.0.10.10  (5.6.11-ndb-7.3.3)id=5 (not connected, accepting connect from any host)

The version string identifies the mainline MySQL version from which the MySQL Cluster release was branched and the version of the NDB storage engine used. For example, the full version string for MySQL Cluster NDB 7.3.2 (the first MySQL Cluster production release based on MySQL Server 5.6) is mysql-5.6.11-ndb-7.3.2. From this we can determine the following:

New MySQL Cluster releases are numbered according to updates in the NDB storage engine, and do not necessarily correspond in a one-to-one fashion with mainline MySQL Server releases. For example, MySQL Cluster NDB 7.3.2 (as previously noted) is based on MySQL 5.6.11, while MySQL Cluster NDB 7.3.1 was based on MySQL 5.6.10 (version string: mysql-5.6.10-ndb-7.3.1).

Compatibility with standard MySQL 5.6 releases. While many standard MySQL schemas and applications can work using MySQL Cluster, it is also true that unmodified applications and database schemas may be slightly incompatible or have suboptimal performance when run using MySQL Cluster (see Section 17.1.6, "Known Limitations of MySQL Cluster"). Most of these issues can be overcome, but this also means that you are very unlikely to be able to switch an existing application datastore—that currently uses, for example, MyISAM or InnoDB—to use the NDB storage engine without allowing for the possibility of changes in schemas, queries, and applications. In addition, the MySQL Server and MySQL Cluster codebases diverge considerably, so that the standard mysqld cannot function as a drop-in replacement for the version of mysqld supplied with MySQL Cluster.

MySQL Cluster development source trees. MySQL Cluster development trees can also be accessed from https://code.launchpad.net/~mysql/:

The MySQL Cluster development sources maintained at https://code.launchpad.net/~mysql/ are licensed under the GPL. For information about obtaining MySQL sources using Bazaar and building them yourself, see Section 2.9.3, "Installing MySQL Using a Development Source Tree".

Currently, MySQL Cluster NDB 7.1, MySQL Cluster NDB 7.2, and MySQL Cluster NDB 7.3 releases are all Generally Available (GA), although we recommend that new deployments use MySQL Cluster NDB 7.3. MySQL Cluster NDB 6.1, MySQL Cluster NDB 6.2, and MySQL Cluster NDB 6.3, are no longer in active development. For an overview of major features added in MySQL Cluster NDB 7.3, see Section 17.1.4, "MySQL Cluster Development History". For an overview of major features added in past MySQL Cluster releases, see MySQL Cluster Development History, and MySQL Cluster Development History.

This chapter represents a work in progress, and its contents are subject to revision as MySQL Cluster continues to evolve. Additional information regarding MySQL Cluster can be found on the MySQL Web site at http://www.mysql.com/products/cluster/.

Additional Resources. More information about MySQL Cluster can be found in the following places: