Oracle RAC负载均衡和透明应用失败切换的配置和测试过程（二、配置实例）

2022-06-21 17:26:32

第2节配置实例
主要包括的是服务器端的init.ora,listener.ora和tnsnames.ora文件以及客户端的tnsnames.ora文件。
针对本项目的双节点的群集设置，主要配置如下：
hostname service name sid name instance_name ORACLE_HOME
======== =========== ========   ============= ===============
node1   test1      rac           rac1         rac1       /oracle/product/9201
node2   test2      rac           rac2         rac2       /oracle/product/9201
2.1 init.ora
所有节点的init.ora 文件必须配置如下：
remote_listener='LISTENERS_RAC'
rac1.local_listener="LISTENER_rac1”
rac2.local_listener="LISTENER_rac2"
# dispatchers="(pro=ipc)(dis=0)"
db_name='rac' /**********可以不用*************/
rac1.instance_name='rac1'
rac2.instance_name='rac2'
2.2 show parameter
既然service_names在init.ora文件中没有规定，它缺省是db_name.db_domain。每一个节点列出它的主机名和instance_name。随着以上的设置，在你启动进程后，当你从第一个节点检查sql 会话时，你将会发现下面的信息：
1）节点一
SQL> show parameter db_name
NAME      TYPE    VALUE
db_name   string    rac
SQL> show parameter db_domain
NAME      TYPE      VALUE
db_domain string
SQL> show parameter service_names
NAME          TYPE      VALUE
service_names string    rac
SQL> show parameter instance_name
NAME              TYPE      VALUE
instance_name     string    rac1
SQL> show parameter listener
NAME                    TYPE      VALUE
local_listener          string    LISTENER_rac1
mts_listener_address    string
mts_multiple_listeners boolean   FALSE
remote_listener         string    LISTENERS_RAC
2）节点二
SQL> show parameter db_name
NAME       TYPE      VALUE
db_name    string    rac
SQL> show parameter db_domain
NAME           TYPE      VALUE
db_domain      string
SQL> show parameter service_names
NAME            TYPE      VALUE
service_names    string    rac
SQL> show parameter instance_name
NAME               TYPE      VALUE
instance_name      string    rac2
SQL> show parameter listener
NAME                    TYPE      VALUE
local_listener         string    LISTENER_rac2
mts_listener_address   string
mts_multiple_listeners boolean   FALSE
remote_listener        string    LISTENERS_RAC
2.3 listener.ora
test1 listener.ora file
LISTENER =
(DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
      )
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
      )
    )
)

SID_LIST_LISTENER =
(SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /oracle/product/9201)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (ORACLE_HOME = /oracle/product/9201)
      (SID_NAME = rac1)
    )
)

Test2 listener.ora file
LISTENER =
(DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
      )
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
      )
    )
)
SID_LIST_LISTENER =
(SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /oracle/product/9201)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (ORACLE_HOME = /oracle/product/9201)
      (SID_NAME = rac2)
    )
)

2.4 tnsnames.ora
test1—test2 and client side tnsnames.ora file
LISTENERS_RAC =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
)
LISTENER_RAC2 =
(ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))

LISTENER_RAC1 =
(ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
RAC2 =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = rac)
      (INSTANCE_NAME = rac2)
    )
)
RAC1 =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = rac)
      (INSTANCE_NAME = rac1)
    )
)

RAC =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
      (LOAD_BALANCE = on)
(FAILOVER=on)
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = rac)
      (failover_mode=(type=select)(method=basic))/********TAF使用的配置**********/
    )
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
)
//////////////////////////////////////////////////////////////
failover =
(DESCRIPTION =
    (enable=broken)
    (LOAD_BALANCE = yes)
    (ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
    (CONNECT_DATA =
      (SERVICE_NAME = rac)
      (failover_mode=(type=select)(BACKUP=cletus)(method=basic))
    )
)
//////////////////////////////////////////////////////////////////
2.5 配置注释
1) LISTENERS_RAC, LISTENER_rac1, LISTENER_rac2是net_service_name (连接描述) for remote_listener和local_listener.在客户端,你并不需要这些参数。
2) failover 是为透明应用失败切换(TAF)测试的net_service_name 。
3) RAC 是客户端的负载平衡的 net_service_name,如果你不需要配置TAF,这有另外一种设置客户端连接负载平衡的配置方法，下面是另外一种办法：
RAC_alternative =
    (DESCRIPTION =
    (ADDRESS_LIST =
      (LOAD_BALANCE = yes)
      (ADDRESS = (PROTOCOL = TCP)(HOST = test1)(PORT = 1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = test2)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = rac)
    )
)
注: (load_balance=yes)可以使Net程序以一种随机的顺序处理地址列表中的侦听器，平衡不同侦听器之间的负载。当被设成OFF，Net程序将以顺序的方式处理直到一个成功。这个参数必须在你的net service name (connect descriptor)正确的配置. 缺省情况下这个参数被设成ON, Load balancing能联系到ADDRESSes和DESCRIPTIONs的设置并且在ADDRESS_LIST里进行规定。如果你使用ADDRESS_LIST，(load_balance=yes)将会在(ADDRESS_LIST=)部分。如果你不使用ADDRESS_LIST, (load_balance=yes)将会在(description=)部分里，我建议不使用(ADDRESS_LIST=) 字句。
4）(failover=on)缺省是在ADDRESS_LISTs, DESCRIPTION_LISTs和一个DESCRIPTIONs的设置里，因此你不需要规定。它是作为connect-time-failover，请注意不要与透明应用切换(TAF)发生冲突。
5）(failover_mode=)：在FAILOVER_MODE参数必须包括在一个net_service_name的CONNECT_DATA部分。
6)这儿在(failover_mode=)里没有(backup=failover)，
7) There is no (backup=failover) in (failover_mode=), this 暗示着
(failover_mode=(type=select)(method=basic)(backup=failover)),它意味着无论是否failover发生，连接的会话将会切换到net_service_name又进行失败切换，当使用PRECONNECT来pre-establish连接时BACKUP应该被规定，需要详细的TAF信息，请参考Oracle官方文档。

本文转自einyboy博客园博客，原文链接：http://www.cnblogs.com/einyboy/archive/2012/11/19/2777876.html，如需转载请自行联系原作者。

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