在安装oracle 11g rac是报错内容如下：
INFO: Checking Single Client Access Name (SCAN)...
INFO: Checking name resolution setup for "racscan"...
INFO: ERROR:
INFO: PRVF-4664 : Found inconsistent name resolution entries for SCAN name "racscan"
INFO: ERROR:
INFO: PRVF-4657 : Name resolution setup check for "racscan" (IP address: 192.168.164.10) failed
INFO: ERROR:
INFO: PRVF-4664 : Found inconsistent name resolution entries for SCAN name "racscan"
INFO: Verification of SCAN VIP and Listener setup failed
由于条件有限，没有使用dns做scan的解析，全部用的host文件。这个错误可以直接忽略！
下面是oracle官网个id解决方法。
Applies to:
Oracle Server - Enterprise Edition - Version: 11.2.0.1 to 11.2.0.2 - Release: 11.2 to 11.2
Information in this document applies to any platform.
Purpose
runInstaller (OUI) reports INS-20802 while running Oracle Cluster Verification Utility post check after successful 11gR2 Grid Infrastructure clusterware (CRS) installation or upgrade:
Installation log - $ORACLE_BASE/oraInventory/logs/installActions{$TIMESTAMP}.log
INFO: PRVF-4664 : Found inconsistent name resolution entries for SCAN name "cluscan.us.oracle.com"
INFO: ERROR:
INFO: PRVF-4657 : Name resolution setup check for "scanclunm" (IP address: 10.4.0.202) failed
If "$GRID_HOME/bin/cluvfy comp scan" is executed, similar message will be reported.
PRVF-4664 PRVF-4657: Found inconsistent name resolution entries for SCAN name
Cause 1. SCAN name is expected to be resolved by local hosts file
SCAN name is resolved by local hosts file (/etc/hosts or %SystemRoot%\system32\drivers\etc\hosts) instead of DNS or GNS
Solution: Oracle strongly recommend to use DNS or GNS for SCAN name resolution as hosts file support only one IP for SCAN
If the intention is to use hosts file for SCAN name resolution, and ping command returns correct SCAN VIP, you can ignore the error and move forward.
If the intention is to use DNS or GNS for SCAN name resolution, comment out entries in local hosts file for SCAN name on all nodes, and re-run "$GRID_HOME/bin/cluvfy comp scan" to confirm.
Cause 2. nslookup fails to find record for SCAN name:
nslookup cluscan.us.oracle.com
..
** server can't find eotcs.us.eot.com: NXDOMAIN
Solution: Engage System Administrator(SA) to check resolver configuration (/etc/resolv.conf on Linux/UNIX), correct any misconfiguration on all nodes and re-run "$GRID_HOME/bin/cluvfy comp scan" to confirm.
Cause 3. SCAN name is canonical name(CNAME record) in DNS
nslookup cluscan.us.oracle.com
..
cluscan.us.oracle.com canonical name = cluscan.a3.oracle.com
Name: cluscan.a3.oracle.com
Address: 10.4.0.201
Name: cluscan.a3.oracle.com
Address: 10.4.0.202
Name: cluscan.a3.oracle.com
Address: 10.4.0.203
Solution: Engage SA to update SCAN record in DNS to A type instead of CNAME type.
Cause 4. DNS is configured properly in DNS but other naming resolution(nis, ldap..) is being used and doesn't have proper SCAN info
Solution: Engage SA to check name resolution switch configuration (/etc/nsswitch.conf onLinux, Solaris and hp-ux or /etc/netsvc.conf on AIX) and correct any misconfiguration on all nodes. Example hosts in nsswitch.conf:
hosts: files dns nis
Once it's corrected, execute "$GRID_HOME/bin/cluvfy comp scan" to confirm
Cause 5. Persistent cache for nscd has incorrect information.
Solution: Engage SA to restart nscd and clear persistent cache on all nodes. Example on Linux
# /sbin/service nscd restart
# /usr/sbin/nscd --invalidate=hosts
Once it's corrected, execute "$GRID_HOME/bin/cluvfy comp scan" to confirm
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原创内容，转载请注明链接，谢谢！
http://blog.csdn.net/aaron8219/article/details/10127987
