實驗環境：RHEL 6.5 + GI 11.2.0.4 + Oracle 11.2.0.4
驗證：RAC 某節點不可用時，其對應VIP是否可用？是否可用於連接數據庫？
[grid@jyrac2 ~]$ more /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
#public ip
192.168.56.150 jyrac1
192.168.56.152 jyrac2
#private ip
10.10.10.11 jyrac1-priv
10.10.10.12 jyrac2-priv
#virtual ip
192.168.56.151 jyrac1-vip
192.168.56.153 jyrac2-vip
#scan ip
192.168.56.160 jyrac-scan
1.節點宕機，對應節點VIP漂移到另一個節點
模擬主機jyrac1宕機，隨之該節點的VIP資源failed over。 此時在主機jyrac2查詢對應的資源信息如下：[grid@jyrac2 ~]$ crsctl stat res -t
--------------------------------------------------------------------------------
NAME TARGET STATE SERVER STATE_DETAILS
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.DATA1.dg
ONLINE ONLINE jyrac2
ora.FRA1.dg
ONLINE ONLINE jyrac2
ora.LISTENER.lsnr
ONLINE ONLINE jyrac2
ora.OCR1.dg
ONLINE ONLINE jyrac2
ora.asm
ONLINE ONLINE jyrac2 Started
ora.gsd
OFFLINE OFFLINE jyrac2
ora.net1.network
ONLINE ONLINE jyrac2
ora.ons
ONLINE ONLINE jyrac2
ora.registry.acfs
ONLINE ONLINE jyrac2
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.LISTENER_SCAN1.lsnr
1 ONLINE ONLINE jyrac2
ora.cvu
1 ONLINE ONLINE jyrac2
ora.jyrac1.vip
1 ONLINE INTERMEDIATE jyrac2 FAILED OVER
ora.jyrac2.vip
1 ONLINE ONLINE jyrac2
ora.jyzhao.db
1 ONLINE OFFLINE Instance Shutdown
2 ONLINE ONLINE jyrac2 Open
ora.oc4j
1 ONLINE ONLINE jyrac2
ora.scan1.vip
1 ONLINE ONLINE jyrac2
2.節點宕機后，另一個節點的網絡信息
查看在主機jyrac2網絡信息：[grid@jyrac2 ~]$ ifconfig -a
eth2 Link encap:Ethernet HWaddr 08:00:27:1A:5A:7A
inet addr:192.168.56.152 Bcast:192.168.56.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe1a:5a7a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3955 errors:0 dropped:0 overruns:0 frame:0
TX packets:8277 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:510869 (498.8 KiB) TX bytes:692985 (676.7 KiB)
eth2:1 Link encap:Ethernet HWaddr 08:00:27:1A:5A:7A
inet addr:192.168.56.153 Bcast:192.168.56.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth2:2 Link encap:Ethernet HWaddr 08:00:27:1A:5A:7A
inet addr:192.168.56.151 Bcast:192.168.56.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth2:3 Link encap:Ethernet HWaddr 08:00:27:1A:5A:7A
inet addr:192.168.56.160 Bcast:192.168.56.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth3 Link encap:Ethernet HWaddr 08:00:27:7C:CD:9F
inet addr:10.10.10.12 Bcast:10.10.10.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe7c:cd9f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:116635 errors:0 dropped:0 overruns:0 frame:0
TX packets:103705 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:81979594 (78.1 MiB) TX bytes:63727783 (60.7 MiB)
eth3:1 Link encap:Ethernet HWaddr 08:00:27:7C:CD:9F
inet addr:169.254.198.12 Bcast:169.254.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:145545 errors:0 dropped:0 overruns:0 frame:0
TX packets:145545 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:130875345 (124.8 MiB) TX bytes:130875345 (124.8 MiB)
3.可ping通宕機節點VIP，但無對應監聽
發現能ping通故障節點VIP，但並沒有對應的監聽程序。 ping可以通，如下：[root@jyrac2 ~]# ping 192.168.56.151
PING 192.168.56.151 (192.168.56.151) 56(84) bytes of data.
64 bytes from 192.168.56.151: icmp_seq=1 ttl=64 time=0.023 ms
64 bytes from 192.168.56.151: icmp_seq=2 ttl=64 time=0.036 ms
64 bytes from 192.168.56.151: icmp_seq=3 ttl=64 time=0.051 ms
64 bytes from 192.168.56.151: icmp_seq=4 ttl=64 time=0.069 ms
^C
--- 192.168.56.151 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3229ms
rtt min/avg/max/mdev = 0.023/0.044/0.069/0.019 ms
沒有監聽，通過此VIP自然連接不上，如下：
[root@jyrac2 ~]# sqlplus system/oracle@192.168.56.151/jyzhao
SQL*Plus: Release 11.2.0.4.0 Production on Thu Nov 3 16:58:31 2016
Copyright (c) 1982, 2013, Oracle. All rights reserved.
ERROR:
ORA-12541: TNS:no listener
Enter user-name:
#查看監聽，確認的確只有scan ip和節點2的ip和vip被監聽；節點1的vip的確是沒有被監聽。
[root@jyrac2 ~]# ps -ef|grep tns
root 15 2 0 09:05 ? 00:00:00 [netns]
grid 2845 1 0 09:07 ? 00:00:00 /opt/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit
grid 6867 1 0 09:34 ? 00:00:00 /opt/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN1 -inherit
root 13951 10953 0 17:17 pts/0 00:00:00 grep tns
[root@jyrac2 ~]# su - grid
[grid@jyrac2 ~]$ lsnrctl status LISTENER
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 03-NOV-2016 17:18:09
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 03-NOV-2016 09:07:20
Uptime 0 days 8 hr. 10 min. 49 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/11.2.0/grid/network/admin/listener.ora
Listener Log File /opt/app/grid/diag/tnslsnr/jyrac2/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.152)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.153)(PORT=1521)))
Services Summary...
Service "+ASM" has 1 instance(s).
Instance "+ASM2", status READY, has 1 handler(s) for this service...
Service "jyzhao" has 1 instance(s).
Instance "jyzhao2", status READY, has 1 handler(s) for this service...
Service "jyzhaoXDB" has 1 instance(s).
Instance "jyzhao2", status READY, has 1 handler(s) for this service...
The command completed successfully
[grid@jyrac2 ~]$ lsnrctl status LISTENER_SCAN1
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 03-NOV-2016 17:18:18
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN1)))
STATUS of the LISTENER
------------------------
Alias LISTENER_SCAN1
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 03-NOV-2016 09:34:20
Uptime 0 days 7 hr. 43 min. 58 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/11.2.0/grid/network/admin/listener.ora
Listener Log File /opt/app/11.2.0/grid/log/diag/tnslsnr/jyrac2/listener_scan1/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER_SCAN1)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.160)(PORT=1521)))
Services Summary...
Service "jyzhao" has 1 instance(s).
Instance "jyzhao2", status READY, has 1 handler(s) for this service...
Service "jyzhaoXDB" has 1 instance(s).
Instance "jyzhao2", status READY, has 1 handler(s) for this service...
The command completed successfully
[grid@jyrac2 ~]$
4.知識點總結
回到本文開頭提出的問題： RAC 某節點不可用時，其對應VIP是否可用？是否可用於連接數據庫？ 答：RAC 某節點不可用時，其對應VIP可ping通。但由於沒有監聽，所以不可用於連接數據庫。最后思考下，VIP既然failover漂移后可以ping通，但卻沒有對應的監聽程序導致節點故障時不能再用此節點的vip連接數據庫，那么VIP設置的意義何在呢？
從網絡上搜索一些資料也可以得知：
VIP 是在出現故障的時候保證不用等待底層的TCP/IP 協議來診斷斷開連接，而使用RAC級別來診斷，這樣會很快。
簡單舉例子來說，就是節點1故障后，其VIP會漂移到節點2；但是由於節點2並沒有對節點1這個VIP地址進行監聽，這樣客戶端就能迅速知道節點1故障，從而切換到節點2；另外，需要注意的是，如果要實現failover，那么tnsnames.ora中要有相應的配置。關於RAC的tnsnames.ora配置具體可參見Oracle RAC客戶端tnsnames.ora相關配置及測試