OCR MASTER NODE:

How to Identify Master Node in ORACLE CLUSTERWARE

1. By searching crsd.l* on all nodes:

grep "OCR MASTER" $ORACLE_BASE/log/$HOST/crsd/crsd.l*

2. Location of automatic OCR backup:

ocrconfig –showbackup -auto

3. OCLUMON

Oclumon manage -get MASTER

4. select MASTER_NODE from v$ges_resource;

Q1:Which property is used to set the master node? What constitutes a master node? You cannot define a node to be master node. All nodes update the database via a heat beat scheme. The first node to detect the lack of a master node (or a missing heart beat from a master node) claims the master role.

Q2:What happens when the master node is down? Another node in the cluster will detect a missing heart beat and claim the master role.

Q3:How do you block incoming traffic to the master node doing the recovery? All nodes should be accepting traffic, including the master node doing recovery. Recovery can be done in small batches so as to not impact incoming traffic.

Q4:How do you set the database connection pool required by recovery operations for all the nodes being recovered? All nodes should be configured with the same resources, as any node can claim the master role in the cluster.

Reference:

Additional Details on Master Node Recovery Scheduling (Doc ID 1635451.1)