SCAN Listeners command and configuration in Oracle RAC Environment

SCAN Listeners

Scan Listener is Single Client Access Name which is introduced in Oracle RAC Environment in 11gR2 version.

Benefits: It provide the single name for client to access any database running in cluster environment.If you add or remove the node from the cluster then no need to modified the client network connectivity.

you can use scan listener feature with two connectivity ways:

EZConnect and Thin JDBC Connect Strings

EZconnet: sqlplus system/manager@rac-scan:1521/orcl

JDBC connect: jdbc:oracle:thin:@rac-scan:1521/orcl

If you face any issue in Scan Listener. you need to check first that scan name is resolved at network level with following command:

nslookup rac-scan

Check the configuration of Scan Listener

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

srvctl config scan
SCAN name: sales1-scan, Network: 1/
SCAN VIP name: scan1, IP: /
SCAN VIP name: scan2, IP: /
SCAN VIP name: scan3, IP: /


Check the status of scan listener

srvctl status scan_listener

Start the scan listener

srvctl start scan_listener

Stop the scan listener

srvctl stop scan_listener


Verify on both RAC nodes it working:

[grid@rac01 ~]$ ps -ef | grep -i tns
grid      9052     1  0 Aug09 ?        00:00:01 /u01/home/11.2.0/grid/bin/tnslsnr LISTENER -inherit
grid      9098     1  0 Aug09 ?        00:00:01 /u01/home/11.2.0/grid/bin/tnslsnr LISTENER_SCAN1 -inherit
grid     21388 20424  0 05:06 pts/1    00:00:00 grep -i tns

[grid@rac01 ~]$

[grid@rac02 ~]$ ps -ef | grep -i tns
grid      1323  1292  0 05:07 pts/0    00:00:00 grep -i tns
grid      9110     1  0 Aug09 ?        00:00:02 /u01/home/11.2.0/grid/bin/tnslsnr LISTENER -inherit
grid     17278     1  0 Aug09 ?        00:00:01 /u01/home/11.2.0/grid/bin/tnslsnr LISTENER_SCAN2 -inherit
grid     17285     1  0 Aug09 ?        00:00:01 /u01/home/11.2.0/grid/bin/tnslsnr LISTENER_SCAN3 -inherit



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