How to find out the master node ?

How to find out the nodes in RAC cluster (or) 
How to find out the master node in Oracle RAC?

There are several ways to find out which is the master node or all the nodes which are part of Oracle RAC cluster.

Use any one of the below.

i) oclumon manage -get master        (in Oracle RAC 12c)


ii) select MASTER_NODE from v$ges_resource;

iii) ocrconfig -manualbackup


iv) check ocssd.log file and search for "master node number".

$ grep "master node number" /u01/app/crs/11.2.0.4/log/`hostname -s`/cssd/ocssd.log




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Oracle oclumon utility/commands

oclumon (Oracle Cluster Health Monitor) in Oracle 11g / 12c RAC

oclumon -help
oclumon version

oclumon debug version 
oclumon debug [log daemon module:log_level] [version]
oclumon debug [log all/osysmond/ologgerd/client debuglevel] [0-3]
oclumon debug log osysmond CRFMOND:3
oclumon debug log ologgerd CRFLOGD:2
oclumon debug log client allcomp:1
oclumon debug log all allcomp:0

oclumon dumpnodeview [[-allnodes] | [-n node1 node2 ... noden] [-last "duration"] | [-s "time_stamp" -e "time_stamp"] [-i interval] [-v]] [-h]
oclumon dumpnodeview -n host01
oclumon dumpnodeview -n racnode2 -last "00:15:00"
oclumon dumpnodeview -n node1 node3 node5 -last "12:00:00"
oclumon dumpnodeview -allnodes -last "00:15:00" -i 30
oclumon dumpnodeview -v -allnodes -alert -last "01:00:00"
oclumon dumpnodeview -allnodes -s "2016-11-04 10:05:00" -e "2016-11-04 10:10:00"
oclumon dumpnodeview -allnodes -warning -v -s "2016-11-04 10:05:00" -e "2016-11-04 10:05:10"

oclumon manage -repos {{changeretentiontime time} | {changerepossize memory_size}} | -get {key1 [key2 ...] | alllogger [-details] | mylogger [-details]}
oclumon manage -get master                        # will give master node
oclumon manage -get master path
oclumon manage -get reppath
oclumon manage -get repsize
oclumon manage -get alllogger -details
oclumon manage -get mylogger
oclumon manage -repos changeretentiontime 86400
oclumon manage -repos changerepossize 6000
oclumon manage -repos reploc /nfs/orarac/chm
oclumon manage -db resize 43200

oclumon showtrail -n node1 -nicid eth0 effectivebw errors -c "red" "yellow" "orange" -last "00:15:00"
oclumon showtrail -n node1 -sys usagepc cpuqlen cpunumprocess memfree numrt numofiosps openfds -c "red" "yellow" "orange" -last "00:15:00" 

oclumon showobjects
oclumon showobjects -n racnode6 -time "2017-10-24 15:00:00"


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