--ORACLE RAC TAF 配置(透明故障转移)
TAF(Transparent Application Failover)即透明应用程序故障转移技术。当初始化连接出现问题无法连接时,该功能可以保证应用程序重新连接到可用服务。在重新连接过程中,之前的活动事务将会被回滚,但在“具体条件”下TAF可以保证SELECT语句不被终止。这也是RAC亮点之一。
所谓的“具体条件”指的就是FAILOVER_MODE中METHOD选择“BASIC”、TYPE选择“SELECT”
TAF的特性:
1:TAF是ORACLE客户端提供的一项特性,使用TAF,对客户端的环境有一定的要求,比如JAVA的JDBC驱动、Oracle客户端的版本等(8i开始支持TAF);
2:大致上TAF可以分为2种,连接时的TAF和会话建立后TAF;
3:TAF本身与是否RAC环境无关,但一般都用在RAC环境,最小程度的减少最应用的影响,单实例环境下也可以使用TAF,这样使用PL/SQL developer连接数据库,即使数据库实例重启,也不需要重新连接;
4:RAC环境下,还可以把TAF配置在服务器端;
5:配置listener.ora文件的GLOBAL_DBNAME参数后将会禁用TAF
1. 查看服务名
col name format a24
col failover_method format a11 heading 'METHOD'
col failover_type format a10 heading 'TYPE'
col failover_retries format 9999999 heading 'RETRIES'
col goal format a10
col clb_goal format a8
col AQ_HA_NOTIFICATIONS format a5 heading 'AQNOT'
select name, failover_method,failover_type, failover_retries,goal, clb_goal,aq_ha_notifications from dba_services;
2 客户端配置TAF
NODE =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = rac-scan.yang.com)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = rac.yang.com)
(FAILOVER_MODE =
(TYPE = SELECT)
(METHOD = BASIC)
(RETRIES = 180)
(DELAY = 5))
)
)
3 服务端配置TAF
srvctl add service -d prdres -s tlres -r "prdres1" -a "prdres2" -P PRECONNECT -e SELECT
srvctl status service -d prdres
其他服务端命令示例:
crs rac service 服务 TAF failover 配置例子
srvctl add service -d ztradej -s S2ztradej -r "ztradej1" -a "ztradej2" -P BASIC -e SELECT
srvctl modify service -d ztradej -s S2ztradej -m BASIC -e SELECT -q TRUE -w 5 -z 180
srvctl add service -d ztradej -s S3ztradej -r "ztradej1" -a "ztradej2" -P BASIC -e SELECT
srvctl modify service -d ztradej -s S3ztradej -m BASIC -e SELECT -q TRUE -w 5 -z 180
srvctl start service -d ztradej -s S3ztradej
srvctl add service -d ztradej -s S4ztradej -r "ztradej1" -a "ztradej2" -P BASIC -e SELECT
srvctl modify service -d ztradej -s S4ztradej -m BASIC -e SELECT -q TRUE -w 5 -z 180
srvctl start service -d ztradej -s S4ztradej
srvctl add service -d ztradej -s S5ztradej -r "ztradej1" -a "ztradej2" -P BASIC -e SELECT
srvctl modify service -d ztradej -s S5ztradej -m BASIC -e SELECT -q TRUE -w 5 -z 180
srvctl start service -d ztradej -s S5ztradej
srvctl stop service -d ztradej -s S5ztradej
srvctl stop service -d ztradej -s S4ztradej
srvctl stop service -d ztradej -s S3ztradej
srvctl stop service -d ztradej -s S2ztradej
srvctl remove service -d ztradej -s S5ztradej
srvctl remove service -d ztradej -s S4ztradej
srvctl remove service -d ztradej -s S3ztradej
srvctl remove service -d ztradej -s S2ztradej
srvctl status service -d ztradej
srvctl relocate service -d ztradej -s S1ztradej -i ztradej2 -t ztradej1
srvctl stop service -d ztradej -s S1ztradej
srvctl remove service -d ztradej -s S1ztradej
srvctl config service -d prdres
srvctl add service -h