DNS

sqlplus, tnsping or lsnrctl Hangs

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sqlplus, tnsping or lsnrctl Hangs I can’t cover all situations in this post, but I have some cases that can share with you. Those hanging all point to one problem: Domain name resolution. Does the database server use DNS to do name resolution? Sometimes, DNS traps the name resolution in an unknown and indefinite loop […]
Public IP

How to Add a Public IP Address to Grid

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Strictly speaking, adding a public IP to server at OS-level is no problem, but you can’t add any public IP to join any node of RAC at grid-level, because the clusterware must determine the public IP by resolving hostname of its node at startup-time. You can only replace it. There’re two possible scenarios of changing […]
SCAN IP

How to Add a SCAN VIP to Grid

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Looking up SCAN name on DNS before adding a SCAN VIP[root@primary01 ~]# nslookup primary-cluster-scanServer:         10.0.0.199Address:        10.0.0.199#53Name:   primary-cluster-scan.example.comAddress: 10.0.0.82Name:   primary-cluster-scan.example.comAddress: 10.0.0.81Name:   primary-cluster-scan.example.comAddress: 10.0.0.83There’re 3 SCAN VIPs for this name.Adding a SCAN VIP to DNS[root@dns ~]# cd /var/named/[root@dns named]# vi example.com.zone[root@dns named]# vi 0.10.zone[root@dns named]# systemctl restart […]
Public IP

How to Change Public IP within Same Subnet of Grid

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Identify which interface that you should modify[grid@oda0 ~]$ oifcfg getif -globalbond0  10.0.18.0  global  publicibbond0  192.168.2.0  global  cluster_interconnect,asmOK, we found bond0 is the public IP interface.Modify /etc/sysconfig/network-scripts/ifcfg-bond0[root@oda0 ~]$ vi /etc/sysconfig/network-scripts/ifcfg-bond0…IPADDR=10.0.18.5#IPADDR=10.0.18.218…Modify /etc/hosts and DNS[root@oda0 ~]$ vi /etc/hosts…10.0.18.5    oda0 oda0.example.com#10.0.18.218    oda0 oda0.example.comRestart network[root@oda0 ~]$ service network restartYou may lost connection to the console.Restart clusterware stack by […]
Listener

How to Resolve The listener supports no services

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The Listener Supports Services
The listener supports no services I newly created a database called SMALLDB, but I can’t see any service registered with the new LISTENER2 which is listening to incoming connections from port 1522. The listener showed “The listener supports no services”. In fact, this message tells us that the listener is working fine, but no dynamic […]
Database

What Symbols are Used in Oracle Database

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Several symbols that are used in Oracle might represent different meanings in different place. Question mark ? ORACLE HOME ? (a Question Mark) in a path string represents the environmental variable of ORACLE_HOME. It’s usually $ORACLE_HOME in UNIX or Linux, %ORACLE_HOME% in Windows. SQL> alter tablespace temp add datafile ‘?/dbs/temp02.dbf’ size 200M; You may also […]
Network

How to Change Subnet of Grid

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Oracle 12c uses 4 types of IP addresses to configure network of RAC:Public IPPrivate IPVirtual IPSCAN IPIn which, Public IP, Virtual IP and SCAN IP are in the same subnet. Up to 4 pairs of Private IP can be set in RAC, which should be in another subnet and used for interconnect redundancy to secure […]
Network

How to Resolve ORA-12170: TNS:Connect timeout occurred

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ORA-12170 At some points, the client sides received intermittent ORA-12170 repeatedly: ORA-12170: TNS:Connect timeout occurred Meanwhile, the server side did not receive any errors either in listener.log or alert.log. Causes Obviously, the failed connections did not reach their destination while errors showed on the client side. Sometimes, it’s a listener time-out to reject connections, but […]