一、基本概念
oracle11gR2 RAC開始引入scan概念，一般通過dns服務器或gns服務器解析scan，也可以使用/etc/hosts文件解析scan，只不過oracle官方不建議這樣做，hosts文件只能解析一個scan ip；另一個方面監聽器前移到$GRID_HOME/network/admin/listener.ora文件，即11g rac監聽器由grid用戶管理，oracle用戶保留文件，但已經不起作用。客戶端文件tnsnames.ora依然在$ORACLE_HOME/network/admin/tnsnames.ora文件。scan的提出徹底做到了rac數據庫對用戶的透明管理，客戶端通過scan域名直接連接數據庫即可（首先客戶端可以解析scan域名），具體由DNS服務器解析域名，這里如果用dns解析scan，最多可以解析3個scan vip，通過scan域名訪問數據庫可以實現scan vip的failover和負載均衡，即只要3個scan vip中存活一個，客戶端應用既可以訪問數據庫。如果采用hosts文件解析scan，只能解析一個scan vip。
oracle 10g rac中監聽器由oracle用戶管理，每個節點上，只有一個監聽器，但是這個監聽器同時監聽public ip和vip，即oracle 10g rac中的監聽器同時承擔着路由選擇和建立連接的功能。10g rac客戶端通過vip連接數據庫。
oracle 11g rac中使用GRID_HOME下的監聽器而不采用ORACLE_HOME 下的監聽器，同時在oracle 11g rac中出現了多個監聽器，使用名稱區分。所以11g rac的監聽器使用grid用戶管理，而不能通過oracle用戶進行管理。11g rac監聽器分本地監聽器（建立連接）和scan監聽器（路由轉發）2種，另外，每一個scan vip都會有一個scan監聽器，並且運行在同一個節點上。即
rac中，每個節點上都運行一個本地監聽器，這個監聽器負責監聽本地的vip。
rac中，會有3個節點上運行scan監聽器。
rac中，scanvip和scan監聽器成對出現。
二、監聽器管理及故障處理
節點1 listener.ora配置：
[grid@node1 admin]$ pwd
/u01/app/11.2.0/grid/network/admin
[grid@node1 admin]$ cat listener.ora
# listener.ora.node1 Network Configuration File: /u01/app/11.2.0/grid/network/admin/listener.ora.node1
# Generated by Oracle configuration tools.
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN3 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN2 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN1 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER1 = ON
LISTENER =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER))
)
)
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER = ON
LISTENER_SCAN3 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN3))
)
)
LISTENER_SCAN2 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN2))
)
)
LISTENER_SCAN1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN1))
)
)
節點2 listener.ora配置：
[grid@node2 admin]$ pwd
/u01/app/11.2.0/grid/network/admin
[grid@node2 admin]$ cat listener.ora
# listener.ora.node2 Network Configuration File: /u01/app/11.2.0/grid/network/admin/listener.ora.node2
# Generated by Oracle configuration tools.
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN3 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN2 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN1 = ON
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER1 = ON
SID_LIST_LISTENER1 =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = orcl)
(ORACLE_HOME = /u01/app/11.2.0/grid)
(SID_NAME = orcl2)
)
)
LISTENER =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER))
)
ADR_BASE_LISTENER = /u01/app/grid
ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER = ON
LISTENER_SCAN3 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN3))
)
LISTENER_SCAN2 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN2))
)
LISTENER_SCAN1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = LISTENER_SCAN1))
)
ADR_BASE_LISTENER_SCAN3 = /u01/app/grid
ADR_BASE_LISTENER_SCAN2 = /u01/app/grid
ADR_BASE_LISTENER_SCAN1 = /u01/app/grid
1、查看scan vip配置
節點1：
[grid@node1 admin]$ srvctl config scan
SCAN name: scan-cluster, Network: 1/192.168.100.0/255.255.255.0/eth0
SCAN VIP name: scan1, IP: /scan-cluster/192.168.100.45
SCAN VIP name: scan2, IP: /scan-cluster/192.168.100.46
SCAN VIP name: scan3, IP: /scan-cluster/192.168.100.47
節點2：
[grid@node2 admin]$ srvctl config scan
SCAN name: scan-cluster, Network: 1/192.168.100.0/255.255.255.0/eth0
SCAN VIP name: scan1, IP: /scan-cluster/192.168.100.45
SCAN VIP name: scan2, IP: /scan-cluster/192.168.100.46
SCAN VIP name: scan3, IP: /scan-cluster/192.168.100.47
2、查看scan vip狀態（靜態）
節點1：
[grid@node1 admin]$ srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node node2
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node node2
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node node1
節點2：
[grid@node2 admin]$ srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node node2
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node node2
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node node1
3、查看scan vip狀態（動態）
節點1：
[oracle@node1 admin]$ srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node node2
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node node2
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node node1
節點2：
[oracle@node2 admin]$ srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node node2
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node node2
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node node1
4、查看scan listener配置
節點1：
[grid@node1 admin]$ 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
節點2：
[grid@node2 admin]$ 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
5、查看scan listener狀態
節點1：
[grid@node1 admin]$ srvctl status scan_listener
SCAN Listener LISTENER_SCAN1 is enabled
SCAN listener LISTENER_SCAN1 is running on node node2
SCAN Listener LISTENER_SCAN2 is enabled
SCAN listener LISTENER_SCAN2 is running on node node2
SCAN Listener LISTENER_SCAN3 is enabled
SCAN listener LISTENER_SCAN3 is running on node node1
節點2：
[grid@node2 admin]$ srvctl status scan_listener
SCAN Listener LISTENER_SCAN1 is enabled
SCAN listener LISTENER_SCAN1 is running on node node2
SCAN Listener LISTENER_SCAN2 is enabled
SCAN listener LISTENER_SCAN2 is running on node node2
SCAN Listener LISTENER_SCAN3 is enabled
SCAN listener LISTENER_SCAN3 is running on node node1
lsnrct命令查看scan vip狀態：
節點1：
[grid@node1 admin]$ lsnrctl status LISTENER_SCAN3
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 25-MAR-2016 16:09:39
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN3)))
STATUS of the LISTENER
------------------------
Alias LISTENER_SCAN3
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 25-MAR-2016 11:24:15
Uptime 0 days 4 hr. 45 min. 23 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/11.2.0/grid/network/admin/listener.ora
Listener Log File /u01/app/11.2.0/grid/log/diag/tnslsnr/node1/listener_scan3/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER_SCAN3)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.100.47)(PORT=1521)))
Services Summary...
Service "orcl" has 2 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
Instance "orcl2", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 2 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
Instance "orcl2", status READY, has 1 handler(s) for this service...
The command completed successfully
6、查看本地監聽器配置
節點1：
[grid@node1 admin]$ srvctl config listener
Name: LISTENER
Network: 1, Owner: grid
Home: <CRS home>
End points: TCP:1521
節點2：
[grid@node2 admin]$ srvctl config listener
Name: LISTENER
Network: 1, Owner: grid
Home: <CRS home>
End points: TCP:1521
7、查看本地監聽器狀態
節點1：
[grid@node1 admin]$ srvctl status listener
Listener LISTENER is enabled
Listener LISTENER is running on node(s): node2,node1
節點2：
[grid@node2 admin]$ srvctl status listener
Listener LISTENER is enabled
Listener LISTENER is running on node(s): node2,node1
lsnrctl查看本地監聽器狀態：
節點1：
[grid@node1 admin]$ lsnrctl status listener
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 25-MAR-2016 16:08:03
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 25-MAR-2016 11:24:17
Uptime 0 days 4 hr. 43 min. 46 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/11.2.0/grid/network/admin/listener.ora
Listener Log File /u01/app/grid/diag/tnslsnr/node1/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.100.41)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.100.42)(PORT=1521)))
Services Summary...
Service "+ASM" has 1 instance(s).
Instance "+ASM1", status READY, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 1 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
The command completed successfully
8、查看本地運行的監聽器
節點1：
[grid@node1 admin]$ ps -ef|grep lsnr
grid 6290 8174 0 16:12 pts/1 00:00:00 grep lsnr
grid 23796 1 0 11:24 ? 00:00:00 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN3 -inherit
grid 23859 1 0 11:24 ? 00:00:00 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit
節點2：
[grid@node2 admin]$ ps -ef|grep lsnr
grid 8649 1 0 11:44 ? 00:00:00 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN2 -inherit
grid 10591 1 0 Mar24 ? 00:00:01 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit
grid 18776 6639 0 16:13 pts/1 00:00:00 grep lsnr
grid 24334 1 0 Mar24 ? 00:00:02 /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN1 -inherit
9、查看數據庫服務的狀態
[grid@node1 admin]$ lsnrctl service
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 25-MAR-2016 16:19:54
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))
Services Summary...
Service "+ASM" has 1 instance(s).
Instance "+ASM1", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:0 refused:0 state:ready
LOCAL SERVER
Service "orcl" has 1 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:3 refused:0 state:ready
LOCAL SERVER
Service "orclXDB" has 1 instance(s).
Instance "orcl1", status READY, has 1 handler(s) for this service...
Handler(s):
"D000" established:0 refused:0 current:0 max:1022 state:ready
DISPATCHER <machine: node1, pid: 11849>
(ADDRESS=(PROTOCOL=tcp)(HOST=node1)(PORT=43836))
The command completed successfully