• What Application Design Considerations must be taken care, when moving to Oracle Real Application Cluster database?
    Post By: admin

Please refer to article "Deploying Applications on Oracle Real Application Cluster" under Knowledge Base section of ORAXperts.

  • Why there are warning messages such as 'No Cluster Interconnect has been specified'?
    Post By: admin

There are warning messages becasue Oracle could not identify the Cluster Interconnect in the cluster database. Either you have not set the database parameetr cluster_interconnects or nothing is set in the OCR. Easiest way to resolve this is to set the value of the database parameter cluster_interconnects to the actual interconnect IP. Other option is to use 'oifcfg' command to set the physcial interconnect in the Oracle Clusterware(CRS).

  • Why do I get the error 'PRKC-1044: Failed to check the remote command execution set for node ..: Connection refused', while applying patch in the Oracle Real Application Cluster database environment even though the user equivalence is set up properly for
    Post By: admin

Oracle's OPatch internal check for node reach ability fails if there is any kind of login banner is enabled or being displayed upon 'oracle' user login. As a workaround you can set 'LogLevel QUIET' in ~/.ssh/config file on all cluster nodes within the cluster to suppress the banner. Make sure you revoke the changes in ~/.ssh/config file after patching.

  • How to check if Oracle Real Application Cluster is installed with third party cluster software in Oracle 10g?
    Post By: admin

Oracle CRS records the third party software information in the ocssd.log logfile under the $ORA_CRS_HOME/log/$HOSTNMAE/cssd directory. Search for text 'skgxn' in ocssd.log file and you will see third party software information there. When Oracle Clusterware is installed on top of third party clusterware, Oracle CRS set the value of css miss count to 600 so this could be another symptom that is evident when Oracle Clusterware is installed on top of third party cluster software such as Sun Cluster, Veritas Cluster etc.

  • Where can I get more information about Oracle Real Application Cluster?
    Post By: admin

Oracle has released comprehensive documentation about Oracle products including Oracle Real Application Cluster. You can access Oracle's official documentation atOTN. There are few books available in the market on Oracle Real Application Cluster. I personally like this book.

  • Why do we need to set the NIC card FULL duplex for Oracle Real Application Cluster?
    Post By: admin

You must set FULL duplex for NIC cards regardless of Oracle Real Application Cluster or not because in HALF duplex mode NIC can not send and recieve network packets at the same time.

  • Can Oracle 9i and 10g Real Application Cluster database co-exist in the same cluster?
    Post By: admin

Yes, both 9i and 10g cluster databases can co-exist in the same cluster. Becasue Oracle Clusterware is mandatory for the 10g RAC database so when you install Oracle Clusterware it will convert the exisitng 9i RAC srvconfig file to Oracle 10g OCR format and after that both 9i and 10g cluster database will use the OCR file. There is no need to run 9i gsd once Oracle Clusterware is installed.

  • Does Oracle RAC require double amount of storage than required for single instance database?
    Post By: admin

NO, Oracle almost require same amount of storgae that is required in single instance database BUT it must be shared storage accessible from all cluster nodes. The extra shared storage is required for UNDO tablespace (because in Oracle RAC each cluster database instance uses its own UNDO tablespace) and cluster files such as OCR, Voting etc.

  • What is difference between Oracle database software binaries of non-cluster and Oracle RAC database?
    Post By: admin

The Oracle software binaries for cluster database uses RAC option, which is not enabled for single database Oracle software binaries but RAC option can be enabled in the single database oracle home by relinking the Oracle software binaries as shown below:

Login as Oracle software owner then change directory to $ORACLE_HOME/rdbms/lib and execut

make -f ins_rdbms.mk rac_on

and finally if the previous commaned executed successfully execute the following command.

make -f ins_rdbms.mk ioracle

Please make sure you shutdown the database instances running from the ORACLE_HOME you are relinking.


  • How can I identify the interconnect being used in Oracle Real Application Clusters 10g?
    Post By: admin

You can identify the interconnect being used by executing the ORADEBUG IPC command as shown below

Login as sysdba on the database server

SQL> show parameter user_dump_dest

ORADEBUG will write the trace file at this location.

SQL> oradebug setmypid 
SQL> oradebug ipc

The above command will write IPC information in trace file under user_dump_destination. The ipc information will look like.

SSKGXPT 0x1a2392c flags SSKGXPT_READPENDING info for network 0  socket no 10 IP UDP 43759 sflags SSKGXPT_WRITESSKGXPT_UP  info for network 1 socket no 0 IP UDP 0...