SCAN listener supports no services

Question

Hi all,
Our's DB: 11.2.0.1.0. Its 2 node cluster.
$srvctl status scan
SCAN VIP scan1 is enabled
SCAN VIP scan1 is running on node1
SCAN VIP scan2 is enabled
SCAN VIP scan2 is running on node1
SCAN VIP scan3 is enabled
SCAN VIP scan3 is running on node2
@node1$ps -ef | grep tnslsnr
oracle xxxxx ..... /u01/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit
oracle xxxx ..... /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN1 -inherit
oracle xxx ..... /u01/app/oracle/product/11.2.0/db_1/bin/tnslsnr LISTENER -inherit
oracle xxx ..... /u01/app/oracle/product/11.2.0/db_1/bin/tnslsnr listener_scan2 -inherit
@node2$ps -ef | grep tnslsnr
oracle xxxx ..... /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN3 -inherit
oracle xxxx ..... /u01/app/11.2.0/grid/bin/tnslsnr LISTENER_SCAN2 -inherit
oracle xxxx ..... /u01/app/11.2.0/grid/bin/tnslsnr LISTENER -inherit
oracle xxxxxxx ..... /u01/app/oracle/product/11.2.0/db_1/bin/tnslsnr listener -inherit
@node1$lsnrctl status listener_scan2
Listener Parameter File //u01/app/11.2.0/grid/network/admin/listener.ora
Listening Endpoints Summary..
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER_SCAN2)))
The listener supports no services
The command completed successfully
??? Though Listener_scan2 is running on node1,why it shows on ps -ef on node 2 ?
Why listener_scan2 processes from ORACLE_HOME instead of CRS_HOME?
Thanks

Answer 1

I assume SCAN name:1521 is in fact a proper IP address or hostname with the port number?
The Oracle instance will attempt to connect to that IP and port to register its services.
If it is a hostname and not IP, then make sure it resolves correctly to an IP address on that server. If name resolution fails, then without an IP for that name, the Oracle instance cannot register its services.
Once you have made sure that hostname resolution works, the next step is to check whether there is in fact a network service on that IP address, listening on that port.
Two methods can be used. The netstat command (run on that server that owns that IP) will show all tcp listener end points. Use the -n switch to display numerics (and not hostnames). The netstat output should contain and entry "+ip_address:1521+ or +*:1521+ - this will confirm that there is a network service on that port for that IP address.
The more detailed method is using the +lsof+ (list of files) command on the SCAN listener process (find the +pid+ and specify it via the +-p+ command line switch). This command will show all open file handles for the specified process - including socket handles. One of these should be on that IP address for port 1521.
If you have confirmed that both the Oracle instance has the correct SCAN details and that the SCAN listener is actually listening on that tcp port and IP, and registration still does not work - then it could be a connectivity problem.
From the +oracle+ o/s account on the db server, test connectivity to that port and IP using +telnet+.