Part IV
Oracle Real Application Clusters Environment Configuration
Chapter 9:
Understanding the Oracle Real Application Clusters Installed Configuration
1,Understanding the Configured Environment in RAC
2,OCR in Oracle RAC
3,Oratab Configurations for Oracle RAC
4,Database Components Created Using DBCA
5,Manageing Undo Tablespaces in RAC
6,Initialization Parameter Files
7,Cofiguring Service Regisration-Related Parameters in RAC
8,Configuring the Listener File (listener.ora)
9,Directory Server Access(ldap.ora File)
10,Net Service Names(tnsnames.ora File)
11,Net Services Profile (sqlnet.ora File)
1,Understanding the Configured Environment in RAC
The NetCA,DBCA configure your environment to meet the requirements for database
creation and EM discovery of RAC databases.
Note:Configuration files created on each node in your cluster database.
2,OCR in Oracle RAC
DBCA uses OCR for storing the configurations for the cluster database that it creates.
The OCR is a shared file in a cluster file system environment.
If you do not use a cluster file system,then you must make this file a shared raw device.
The OUI automaticaly initializes the OCR during the Oracle Clusterware installation.
3,Oratab Configurations for Oracle RAC
/etc/oratab
Oracle creates an entry for each RAC database in the "oratab" configuration file. Oralce
EM uses this file during service discovery to determine the name of the RAC database,and
to determine whether the database should be automatically started when system is restarted.
The database entry has the following syntax:
db_unique_name:$ORACLE_HOME:N
N indicates that the database should not be started at restart time.
eg:
db:/private/system/db:N
+ASM1:/u01/app/oracle/product/10.2.0/db_1:N
devdb:/u01/app/oracle/product/10.2.0/db_1:N
4,Database Components Created Using DBCA
Tablespaces and Data files
Control Files
Redo Log Files
-------------------------------------------------------------------------------------------
|Tablespace Name | Contents |
-------------------------------------------------------------------------------------------
|SYSTEM |Consists of the data dictionary,including definitions of tables|
| | ,views,and stored procedured needed by the database.Oracle |
| | automatically maintains information in this tablespace. |
-------------------------------------------------------------------------------------------
|SYSAUX |An auxiliary system tablespace that containts the DRSYS
| |(contains data for OracleText),CWMLITE(contains the OLAP schemas)
| | XDB(for XML features),ODM(for Oracle Data Mining),TOOLS(contains
| |EM tables),INDEX,EXAMPLE,and OEM-REPO tablespaces.
-------------------------------------------------------------------------------------------
|USERS |Consists of application data.As you create and enter data into
| |tables,Oracle fills this space with your data.
-------------------------------------------------------------------------------------------
|TEMP |Contains temporary tables and indexes created during SQL
| |statement processing.You may need to expand this tablespace if
| |you are runnin a SQL statement that involves significant sorting
| |,such as ANALYZE COMPUTE STATISTICS on a very large table,or the
| |constructs GROUP BY,ORDER BY ,or DISTINCT
--------------------------------------------------------------------------------------------
|UNDOTBSn |These are the undo tablespaces for each instance that DBCA creates
| |for automatic undo management
---------------------------------------------------------------------------------------------
|RBS |If you do not use automatic undo management,then Oracle uses the
| |RBS tablespace for the rollback segments.
---------------------------------------------------------------------------------------------
7,Cofiguring Service Regisration-Related Parameters in RAC
Two key benefits of RAC are connection load balancing and failover.
RAC extends the ability of single-instance Oracle database load balancing,where connections
are distributed among local dispatchers,to the balancing of connections among all instances
in a cluster database.
In addition,RAC provides failover by configuring multiple listeners on multiple nodes to
manage client connection requests for the same database service.
Connection load balancing and failover increase availability by taking advantage of the
redundant resources within a cluster database.
These features,however,required cross instance registration.
监听器是Oracle基于服务器端的一种网络服务，主要用于监听客户端向数据库服务器端提出的连接请求。既然是基于服务器端的服务，那么它也只存在于数据库服务器端，进行手机监听器的设置也是在数据库服务器端完成的。
二、本地服务名(Tnsname)
Oracle客户端与服务器端的连接是通过客户端发出连接请求，由服务器端监听器对客户端连接请求进行合法检查，如果连接请求有效，则进行连接，否则拒绝该连接。
本地服务名是Oracle客户端网络配置的一种，另外还有Oracle名字服务器(Oracle Names Server)等。Oracle常用的客户端配置就是采用的本地服务名，本文中介绍的也主要是基于本地服务名的配置。
三、Oracle网络连接配置方法
配置Oracle服务器端与客户端都可以在其自带的图形化Oracle网络管理器(Oracle Net Manager)里完成(强烈建议在这个图形化的工具下完成Oracle服务端或客户端的配置)。在Windows下，点击“开始/程序/Oracle - OraHome92/Configuration and Migration Tools/Net Manager”启动Oracle网络管理器工具，在Linux/Unix下，利用netmgr命令来启动图形化Oracle网络管理器
四、Oracle监听器配置(LISTENER)
选中该名称，选中窗口右侧栏下拉选项中的“监听位置”，点击添加地址按钮。在出现的网络地址栏的协议下拉选项中选中 “TCP/IP”，主机文本框中输入主机名称或IP地址(如果主机即用作服务端也作为客户端，输入两项之一均有效;如果主机作为服务端并需要通过网络连接，建议输入IP地址)，端口文本框中输入数字端口，默认是1521，也可以自定义任意有效数字端口。
