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:
复制
RACDB = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.170)(PORT = 1521)) ) (CONNECT_DATA = (SERVICE_NAME = racdb.chenxu.yo2.cn) ) )
1.
2.
3.
4.
5.
6.
7.
8.
9.
测试连接:
复制
SQL> conn sys/chenxu@racdb as sysdba 已连接｡ SQL> SQL> show parameter instance_name NAME TYPE VALUE ------------------------------------ ----------- --------------------- instance_name string RACDB1
1.
2.
3.
4.
5.
6.
7.
8.
#p#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:
复制
[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) ) )
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
#p#3､在初始化参数中设置参数remote_listeners
复制
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
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
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｡
复制
[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
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
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:
复制
ERROR: ORA-12545: 因目标主机或对象不存在,连接失败
1.
2.
#p#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:
复制
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
1.
2.
3.
4.
5.
5､通过客户端测试RAC负载均衡配置
复制
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
1.
2.
3.
4.
5.
6.
7.
开启sqlplus_2:
复制
SQL> conn sys/chenxu@racdb as sysdba 已连接｡ SQL> show parameter instance_name NAME TYPE VALUE ------------------------------------ ----------- ------------- instance_name string RACDB2
1.
2.
3.
4.
5.
6.
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｡
