Oracle11g修改RAC SCAN IP
在11gR2中，引入了SCAN（Single Client Access Name）的特性，该特性的好处在于，在数据库与客户端之间，添加了一层虚拟的服务层，就是所谓的scan ip以及scan ip listener，在客户端仅需要配置scan ip的tns信息，通过scan ip listener，连接后台集群数据库。这样，不论集群数据库是否有添加或者删除节点的操作，均不会对client产生影响。当有客户端应用程序使用SCAN ip访问数据库时，scan listener会将连接转发到local listener上。
RAC=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=SCAN)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=RAC)))Client should connect to the SCAN name -> scan listener, scan listener will redirect the connection(sometimes beneath) to the node VIP, and all succeeding procedures are same with the previous versions. 和SCAN ip 相关的ip信息在SCAN 资源创建的时候就被初始化了。在不使用GNS的情况下：任何对DNS和/etc/hosts 中SCAN 中的变更都不会自动同步到Clusterware中而是要手工执行相关的更新操作。下面介绍一下修改scan ip的具体步骤：实验环境：版本：Clusterware ：11.2.0.2database ：11.2.0.1旧scan ip10.250.7.210新scan ip10.250.7.14110.250.7.14210.250.7.1431 查看scan ip的状态信息：grid@rac1:/home/grid>srvctl config scanSCAN 名称: scan, 网络: 1/10.250.7.0/255.255.255.0/eth0SCAN VIP 名称: scan1, IP: /scan/10.250.7.210grid@rac1:/home/grid>2 停止scan_listener ，scan 应用grid@rac1:/home/grid>srvctl stop scan_listenergrid@rac1:/home/grid>srvctl stop scan3 确认 scan_listener,scan 的状态grid@rac1:/home/grid>srvctl status scan_listenerSCAN 监听程序 LISTENER_SCAN1 已启用SCAN 监听程序 LISTENER_SCAN1 未运行grid@rac1:/home/grid>srvctl status scanSCAN VIP scan1 已启用SCAN VIP scan1 未运行grid@rac1:/home/grid>crs_stat -t | grep scan ora.scan1.vip ora....ip.type OFFLINE OFFLINE grid@rac1:/home/grid>grid@rac1:/home/grid>grid@rac1:/home/grid>crs_stat -t | grep lsnrora....ER.lsnr ora....er.type ONLINE ONLINE rac1 ora....N1.lsnr ora....er.type OFFLINE OFFLINE ora....C1.lsnr application ONLINE ONLINE rac1 ora....C2.lsnr application ONLINE ONLINE rac24 在所有节点中 /etc/hosts 文件中修改 scan 对应的ip：10.250.7.141 scan10.250.7.142 scan10.250.7.143 scangrid@rac1:/home/grid>srvctl modify scan -h修改 SCAN 名称。用法: srvctl modify scan -n <scan_name> -n <scan_name> 域名限定的 SCAN 名 -h 输出用法grid 用户无权更改scan ip，必须使用root权限grid@rac1:/home/grid>srvctl modify scan -n scan PRCS-1034 : 无法修改单客户机访问名 scanPRCR-1071 : 无法注册或更新 资源类型 ora.scan_vip.typeCRS-0245: User does not have enough privilege to perform. the operation[root@rac1 ~]# /opt/11202/11.2.0/grid/bin/srvctl modify scan -n scan5 变更后，进行确认：[root@rac1 ~]# /opt/11202/11.2.0/grid/bin/srvctl config scanSCAN 名称: scan, 网络: 1/10.250.7.0/255.255.255.0/eth0SCAN VIP 名称: scan1, IP: /scan/10.250.7.141 <====只有一个scan ip对于/etc/hosts文件解析scan ip,因为不能做轮训的负载均衡，所以这时候scan ip就只能有一个了。6 重新启动scan，scan_listener grid@rac1:/home/grid>srvctl start scangrid@rac1:/home/grid>srvctl start scan_listener7 确认scan 和scan_listener.ora的状态：grid@rac1:/home/grid>crs_stat -t | grep scanora.scan1.vip ora....ip.type ONLINE ONLINE rac2 grid@rac1:/home/grid>crs_stat -t | grep lsnrora....ER.lsnr ora....er.type ONLINE ONLINE rac1 ora....N1.lsnr ora....er.type ONLINE ONLINE rac2 ora....C1.lsnr application ONLINE ONLINE rac1 ora....C2.lsnr application ONLINE ONLINE rac2进行ping测试grid@rac1:/home/grid>ping 10.250.7.141PING 10.250.7.141 (10.250.7.141) 56(84) bytes ofdata.64 bytes from 10.250.7.141: icmp_seq=1 ttl=64 time=1.52 ms64 bytes from 10.250.7.141: icmp_seq=2 ttl=64 time=0.226 ms--- 10.250.7.141 ping statistics ---2 packets transmitted, 2 received, 0% packet loss, time 1000msrtt min/avg/max/mdev = 0.226/0.873/1.520/0.647 msgrid@rac1:/home/grid>ping 10.250.7.142PING 10.250.7.142 (10.250.7.142) 56(84) bytes of data. 与修改private ip ，vip 不一样，修改scan ip 无需停止数据库实例，asm 或者重启crs，相对比较简单！