最近部署一个两节点Oracle RAC 环境，刚刚开始没怎么留意，但当在使用的时候竟然scan-ip无法通过客户端登陆使用，但是在两个节点上可正常使用，此外vip无论在节点上还是其他客户端使用完全ok 。
在安装GI的时候最后报错，但经查看官方文档说是可能scan-ip写到hosts文件中了，但本人环境中三个scan-ip均为加入到hosts文件中，故此直接忽略掉该报错。
下面是本人详细的排错过程：
1. 在任意节点上使用tnsnames.ORA透过scan-ip登陆数据库：
[grid@RAC01 admin]$ tnsping RACDB
TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 02-JAN-2014 18:41:16
Copyright (c) 1997, 2009, Oracle. All rights reserved.
Used parameter files:
/u/app/11.2.0/grid/network/admin/sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.134.30.50)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = RACDB)))
OK (0 msec)
[grid@RAC01 admin]$ sqlplus scott/testpassword@RACDB
SQL*Plus: Release 11.2.0.1.0 Production on Thu Jan 2 18:41:27 2014
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL>
2. 检查RAC上的scan-ip配置：
[grid@RAC01 ~]$ srvctl config scan
SCAN name: RACSCAN.localdomain., Network: 1/10.134.30.0/255.255.255.0/eth0
SCAN VIP name: scan1, IP: /RACSCAN.localdomain/10.134.30.50
SCAN VIP name: scan2, IP: /RACSCAN.localdomain/10.134.30.51
SCAN VIP name: scan3, IP: /RACSCAN.localdomain/10.134.30.52
[grid@RAC01 ~]$ srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1521
3. DNS测试：
[root@RAC01 ~]# nslookup RACSCAN.localdomain.
Server: 10.134.30.27
Address: 10.134.30.27#53
Name: RACSCAN.localdomain
Address: 10.134.30.52
Name: RACSCAN.localdomain
Address: 10.134.30.50
Name: RACSCAN.localdomain
Address: 10.134.30.51
[grid@RAC01 ~]$ nslookup 10.134.30.50
Server: 10.134.30.27
Address: 10.134.30.27#53
50.30.134.10.in-addr.arpa name = RACSCAN.localdomain.
[grid@RAC01 ~]$ nslookup 10.134.30.51
Server: 10.134.30.27
Address: 10.134.30.27#53
51.30.134.10.in-addr.arpa name = RACSCAN.localdomain.
[grid@RAC01 ~]$ nslookup 10.134.30.52
Server: 10.134.30.27
Address: 10.134.30.27#53
52.30.134.10.in-addr.arpa name = RACSCAN.localdomain.