how to find the master node

Hi All,

Since starting whenever I had attended any interview for RAC DBA, one question is very common to me. i.e. ‘how to find the master node ??’

Every time, I tried my best to justified but never have appropriate answer. No worry now. Soon, many of you will not be facing this situation.

Let me 1^st give you small back ground this.

There are two type of node at Clusterware level. One is Mater node and other is Master node for specific resource or block or object. Which node is to be work as Master node is decided by Clusterware synchronization Service. This is the node which first get activated during the RAC node startup. This node manage most of the resource in RAC database (I write most resource because not all the resource manages by Master Node).

Let’s check how to find the master node:

$ cat /p01/crs/oracle/log/jay1/cssd/ocssd* |grep master
[    CSSD]CLSS-3001: local node number 1, master node number 1
[    CSSD]CLSS-3001: local node number 1, master node number 1
[    CSSD]CLSS-3001: local node number 1, master node number 1
[    CSSD]CLSS-3001: local node number 1, master node number 1
[    CSSD]CLSS-3001: local node number 1, master node number 1

 Above output confirm that currently master node is 1.

You can also from

$ cd /p01/crs/oracle/log/jay1/cssd

$ cat grep -i "master node" ocssd.log | tail -1

[    CSSD]CLSS-3001: local node number 1, master node number  

If someone this as tough, I have  one mode simple idea to find master node.  As I confirms master node manage the resource, OCR backup is also maintain by master node.

Let’s check now:

$ ocrconfig -showbackup

jay1     2011/08/30 10:30:36     /u01/crs/oracle/cdata/crs

jay1     2011/08/30 06:30:35     /u01/crs/oracle/cdata/crs

jay1     2011/08/30 02:30:35     /u01/crs/oracle/cdata/crs

jay1     2011/08/28 14:30:27     /u01/crs/oracle/cdata/crs

jay1     2011/08/21 14:29:53     /u01/crs/oracle/cdata/crs

Hopefully, now you will rock this MASTER NODE QUESTION !!!!

Thanks.