--ndb-connectstring options, which are explained elsewhere in this chapter, possibly with additional MySQL server options as well.
An SQL node is actually just a specialized type of API node, which designates any application which accesses MySQL Cluster data. Another example of an API node is the ndb_restore utility that is used to restore a cluster backup. It is possible to write such applications using the NDB API. For basic information about the NDB API, see Getting Started with the NDB API.
SQL节点（SQL node）:这种节点是用于访问集群数据的。对于MySQL集群来讲，一个SQL节点是一个传统的MySQL服务，它使用NDBCLUSTER存储引擎。一个SQL节点是通过mysqld命令的--ndbcluster和--ndb-connectstring参数来启动的进程，该选项在本章的其他地方会解释到，用其他的MySQL服务选项也可以做到。
一个SQL节点实际上只是API node的一种专用类型，该类型的节点指定了任何可以访问MySQL集群数据的应用程序。API node的另外一个例子是node_restore功能，它能够被用来恢复一个集群备份。用NDB API去写应用程序是有可能做到的，有关于NDB API的基本信息，请见Getting Started with the NDB API.
Important The Memcache API for MySQL Cluster, implemented as the loadable ndbmemcache storage engine for memcached version 1.6 and later, can be used to provide a persistent MySQL Cluster data store, accessed using the memcache protocol. The standard memcached caching engine is included in the MySQL Cluster NDB 7.3 distribution. Each memcached server has direct access to data stored in MySQL Cluster, but is also able to cache data locally and to serve (some) requests from this local cache.For more information, see ndbmemcache—Memcache API for MySQL Cluster. Management clients. These clients connect to the management server and provide commands for starting and stopping nodes gracefully, starting and stopping message tracing (debug versions only), showing node versions and status, starting and stopping backups, and so on. An example of this type of program is the ndb_mgm management client supplied with MySQL Cluster (see Section 18.4.5, “ndb_mgm — The MySQL Cluster Management Client”). Such applications can be written using the MGM API, a C-language API that communicates directly with one or more MySQL Cluster management servers. For more information, see The MGM API.Cluster log: Keeps a record of all desired reportable events for the cluster as a whole.
Node log: A separate log which is also kept for each individual node.
事件日志：MySQL集群通过种类（启动，关机，错误，检查点等等），优先级和严重性的事件产生日志。一个有关完整的报告性事件的监听，可以在Section 18.5.6,“Event Reports Generated in MySQL Cluster”文章中找到。事件日志在这里有两种类型：
l 集群日志：针对于集群，以保存一份期望的可报告性的事件记录作为一个整体。
l 节点日志：一个单独的日志维护着每一个单一的节点。
Note