首先确定，在mysql的'plugin_dir'下有ha_innodb_plugin.so和ha_innodb.so两个文件
查询'plugin_dir'的路径可以用以下命令
mysql> show variables like 'plugin_dir';
+---------------+-----------------------------------+
| Variable_name | Value                             |
+---------------+-----------------------------------+
| plugin_dir    | /usr/local/mysql/lib/mysql/plugin |
+---------------+-----------------------------------+
1 row in set (0.01 sec)
如果没有找到，在您的mysql编译目录里有下面的目录文件(内置的innodb和innodb_plugin)
storage/innobase/.libs/ha_innodb.so
storage/innodb_plugin/.libs/ha_innodb_plugin.so
您需要把它们(ha_innodb_plugin.so和ha_innodb.so)拷贝到mysql的plugin目录中(/usr/local/mysql/lib/mysql/plugin)
接下来就是在mysql命令行安装一下
# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 5.1.36-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show engines;
+------------+---------+-----------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                   | Transactions | XA   | Savepoints |
+------------+---------+-----------------------------------------------------------+--------------+------+------------+
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                     | NO           | NO   | NO         |
| CSV        | YES     | CSV storage engine                                        | NO           | NO   | NO         |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables | NO           | NO   | NO         |
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance    | NO           | NO   | NO         |
+------------+---------+-----------------------------------------------------------+--------------+------+------------+
4 rows in set (0.00 sec)
mysql> INSTALL PLUGIN InnoDB SONAME 'ha_innodb.so';
Query OK, 0 rows affected (0.69 sec)
mysql> show engines;
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| Engine     | Support | Comment                                                    | Transactions | XA   | Savepoints |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
| InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| CSV        | YES     | CSV storage engine                                         | NO           | NO   | NO         |
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                      | NO           | NO   | NO         |
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance     | NO           | NO   | NO         |
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables  | NO           | NO   | NO         |
+------------+---------+------------------------------------------------------------+--------------+------+------------+
5 rows in set (0.00 sec)

OK,大功告成