Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
|
Configuring MySQL Cluster requires working with two files:
my.cnf: Specifies options for all MySQL Cluster
executables. This file, with which you should be familiar with from previous work with MySQL, must be
accessible by each executable running in the cluster.
config.ini: This file, sometimes known as the global configuration file, is read only by the MySQL Cluster management
server, which then distributes the information contained therein to all processes participating in the
cluster. config.ini contains a description of each node involved in the
cluster. This includes configuration parameters for data nodes and configuration parameters for
connections between all nodes in the cluster. For a quick reference to the sections that can appear in
this file, and what sorts of configuration parameters may be placed in each section, see Sections
of the config.ini File.
Caching of configuration data. In MySQL Cluster NDB 7.3, MySQL Cluster uses stateful configuration. Rather than reading the global configuration file every time the management server is restarted, the management server caches the configuration the first time it is started, and thereafter, the global configuration file is read only when one of the following conditions is true:
The management server is started using the --initial
option. In this case, the global configuration file is re-read, any existing cache files are
deleted, and the management server creates a new configuration cache.
The management server is started using the --reload
option. In this case, the management server compares its cache with the global configuration file.
If they differ, the management server creates a new configuration cache; any existing configuration
cache is preserved, but not used. If the management server's cache and the global configuration file
contain the same configuration data, then the existing cache is used, and no new cache is created.
The management server is started using a --config-cache option. This option can be used to force the management
server to bypass configuration caching altogether. In this case, the management server ignores any
configuration files that may be present, always reading its configuration data from the config.ini file instead.
No configuration cache is found. In this case, the management server reads the global configuration file and creates a cache containing the same configuration data as found in the file.
Configuration cache files. The management server by default creates configuration cache files in a
directory named mysql-cluster in the MySQL installation directory. (If you build
MySQL Cluster from source on a Unix system, the default location is /usr/local/mysql-cluster.)
This can be overridden at runtime by starting the management server with the --configdir option. Configuration cache files are binary files named according to
the pattern ndb_, where node_id_config.bin.seq_idnode_id
is the management server's node ID in the cluster, and seq_id is a
cache idenitifer. Cache files are numbered sequentially using seq_id,
in the order in which they are created. The management server uses the latest cache file as determined by the
seq_id.
It is possible to roll back to a previous configuration by deleting later configuration cache
files, or by renaming an earlier cache file so that it has a higher seq_id. However, since configuration cache files are written
in a binary format, you should not attempt to edit their contents by hand.
For more information about the --configdir, --initial,
and --reload options for the MySQL Cluster management server, see Section
17.4.4, "ndb_mgmd — The MySQL Cluster Management Server
Daemon".
We are continuously making improvements in Cluster configuration and attempting to simplify this process. Although we strive to maintain backward compatibility, there may be times when introduce an incompatible change. In such cases we will try to let Cluster users know in advance if a change is not backward compatible. If you find such a change and we have not documented it, please report it in the MySQL bugs database using the instructions given in Section 1.7, "How to Report Bugs or Problems".