oracle10g服务器端RAC负载均衡配置代码

前面我们介绍了RAC的客户端负载均衡配置，接下来就到了服务器端RAC负载均衡配置的具体代码介绍了，通过两方面的配置和测试之后，整个负载均衡才能完全的设置好。那么就让我们赶紧来看一下啊具体的服务器端RAC负载均衡配置内容吧。 从Oracle 10g开始,服务器端

前面我们介绍了RAC的客户端负载均衡配置，接下来就到了服务器端RAC负载均衡配置的具体代码介绍了，通过两方面的配置和测试之后，整个负载均衡才能完全的设置好。那么就让我们赶紧来看一下啊具体的服务器端RAC负载均衡配置内容吧。

从Oracle 10g开始,服务器端负载均衡可以根据RAC中各节点的负荷及连接数情况,而判定将新的客户端连接分配到负荷最小的节点上去?RAC中各节点的PMON进程每3秒会将各自节点的负荷(包括LOAD?最大LOAD?CPU使用率)及连接数更新到service_register里面,然后假如节点的负荷有发生变化,将会通知到监听程序,由监听程序再决定新的客户端连接分配至哪个节点?假如RAC中一个节点的监听失败了,PMON每一分钟会去检查一次是否已经恢复正常?

服务器端的监听配置是在各节点的tnsnames.ora里面添加一个连接到各个节点监听的条目,然后再在初始化参数里面设置remote_listeners这个参数?

1?测试客户端的TNS

修改客户端tnsnames.ora的文件,内容如下:

RACDB =  
  (DESCRIPTION =  
    (ADDRESS_LIST =  
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.170)(PORT = 1521))  
    )  
    (CONNECT_DATA =  
      (SERVICE_NAME = racdb.chenxu.yo2.cn)  
    )  
  ) 

测试连接:

SQL>  conn sys/chenxu@racdb as sysdba  
已连接?  
SQL>  
SQL> show parameter instance_name   
 
NAME                                 TYPE        VALUE  
------------------------------------ ----------- ---------------------  
instance_name                        string      RACDB1  

2?配置服务器端TNS

服务器端的监听配置是在各节点的tnsnames.ora里面添加一个连接到各个节点监听的条目(红色代码),在服务器端每个节点的tnsnames.ora里面的内容如下:

[root@NODE01 admin]# pwd  
/orac/orahome/oracle/product/10.2.0/db_1/network/admin  
[root@NODE01 admin]#  
[root@NODE01 admin]# more tnsnames.ora  
# tnsnames.ora Network Configuration File: /orac/orahome/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora  
# Generated by Oracle configuration tools.  
 
RACDB1 =  
  (DESCRIPTION =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip01)(PORT = 1521))  
    (CONNECT_DATA =  
      (SERVER = DEDICATED)  
      (SERVICE_NAME = RACDB.chenxu.yo2.cn)  
      (INSTANCE_NAME = RACDB1)  
    )  
  )  
 
RACDB =  
  (DESCRIPTION =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip01)(PORT = 1521))  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip02)(PORT = 1521))  
    (LOAD_BALANCE = yes)  
    (CONNECT_DATA =  
      (SERVER = DEDICATED)  
      (SERVICE_NAME = RACDB.chenxu.yo2.cn)  
    )  
  )  
 
LISTENERS_RACDB =  
  (ADDRESS_LIST =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip01)(PORT = 1521))  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip02)(PORT = 1521))  
  )  
 
RACDB2 =  
  (DESCRIPTION =  
    (ADDRESS = (PROTOCOL = TCP)(HOST = vip02)(PORT = 1521))  
    (CONNECT_DATA =  
      (SERVER = DEDICATED)  
      (SERVICE_NAME = RACDB.chenxu.yo2.cn)  
      (INSTANCE_NAME = RACDB2)  
    )  
  ) 

3?在初始化参数中设置参数remote_listeners

SQL> conn sys/chenxu@racdb as sysdba  
已连接?  
SQL> show parameter remote_listener  
 
NAME                                 TYPE        VALUE  
------------------------------------ ----------- ------------------------  
remote_listener                      string  
SQL>  
SQL> alter system set remote_listener='LISTENERS_RACDB' sid='*';  
#(reset命令可以撤销设置,恢复默认值)  
系统已更改?  
SQL>  
SQL> show parameter remote_listener  
NAME                                 TYPE        VALUE  
------------------------------------ ----------- ---------------------  
remote_listener                      string      LISTENERS_RACDB 

正确配置参数后,通过lsnrctl status命令看到在监听启动以后,可以看到监听器上有2个instance?

[root@NODE01 bin]# lsnrctl status  
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 18-DEC-2008 05:40:08  
Copyright (c) 1991, 2005, Oracle.  All rights reserved.  
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))  
STATUS of the LISTENER  
------------------------  
Alias                     LISTENER_NODE01  
Version                   TNSLSNR for Linux: Version 10.2.0.1.0 - Production  
Start Date                18-DEC-2008 00:18:07  
Uptime                    0 days 5 hr. 22 min. 1 sec  
Trace Level               off 
Security                  ON: Local OS Authentication  
SNMP                      OFF 
 
Listener Parameter File   /orac/orahome/oracle/product/10.2.0/db_1/network/admin/listener.ora  
Listener Log File         /orac/orahome/oracle/product/10.2.0/db_1/network/log/listener_node01.log  
Listening Endpoints Summary...  
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.1.170)(PORT=1521)))  
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.1.180)(PORT=1521)))  
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))  
 
Services Summary...  
Service "+ASM" has 1 instance(s).  
  Instance "+ASM1", status BLOCKED, has 1 handler(s) for this service...  
Service "+ASM_XPT" has 1 instance(s).  
  Instance "+ASM1", status BLOCKED, has 1 handler(s) for this service...  
Service "RACDB.chenxu.yo2.cn" has 2 instance(s).  
  Instance "RACDB1", status READY, has 2 handler(s) for this service...  
  Instance "RACDB2", status READY, has 1 handler(s) for this service...  
Service "RACDBXDB.chenxu.yo2.cn" has 2 instance(s).  
  Instance "RACDB1", status READY, has 1 handler(s) for this service...  
  Instance "RACDB2", status READY, has 1 handler(s) for this service...  
Service "RACDB_XPT.chenxu.yo2.cn" has 2 instance(s).  
  Instance "RACDB1", status READY, has 2 handler(s) for this service...  
  Instance "RACDB2", status READY, has 1 handler(s) for this service...  
The command completed successfully 

这时在客户端用sqlplus连接服务器数据库可能会出现如下错误:

ERROR:  
ORA-12545: 因目标主机或对象不存在,连接失败 

4?解决ORA-12545连接失败问题

配置客户端的Hosts文件

通过在客户端的Hosts文件中加入对两个服务名的名字解析可以解决ORA-12545问题?在windows下Hosts文件在C:\WINDOWS\system32\drivers\etc目录下,在linux修改/etc/hosts文件的内容?添加如下内容:

192.168.1.170   node01  
192.168.1.171   node02  
其中node01?node02为服务器节点的主机名?  
[root@NODE01 bin]# hostname  
NODE01  

5?通过客户端测试RAC负载均衡配置

开启sqlplus_1:  
SQL> conn sys/chenxu@racdb as sysdba  
已连接?  
SQL> show parameter instance_name  
NAME                                 TYPE        VALUE  
------------------------------------ ----------- ---------------  
instance_name                        string      RACDB1 

开启sqlplus_2:

SQL>  conn sys/chenxu@racdb as sysdba  
已连接?  
SQL>  show parameter instance_name  
NAME                                 TYPE        VALUE  
------------------------------------ ----------- -------------  
instance_name                        string      RACDB2 

可以看到客户端能够连接到实例RACDB2,说明基于服务器端RAC负载均衡配置成功?