How to delete MGMTDB IN RAC

 [root@cogni01 disks]# ps -ef |grep pmon

oracle    5422     1  0 13:12 ?        00:00:00 asm_pmon_+ASM1

oracle    6442     1  0 13:13 ?        00:00:00 mdb_pmon_-MGMTDB

oracle   12510     1  0 13:19 ?        00:00:00 ora_pmon_lmnx1

root     20892  4763  0 13:35 pts/0    00:00:00 grep --color=auto pmon

[root@cogni01 disks]# free -m

              total        used        free      shared  buff/cache   available

Mem:           4900        2793          42        1241        2065         687

Swap:          5119        1190        3929

[root@cogni01 disks]# crsctl stop res ora.crf -init

bash: crsctl: command not found...

[root@cogni01 disks]# . oraenv

ORACLE_SID = [root] ? +ASM1

The Oracle base has been set to /u01/app/oracle

[root@cogni01 disks]# crsctl stop res ora.crf -init

CRS-2673: Attempting to stop 'ora.crf' on 'cogni01'

CRS-2677: Stop of 'ora.crf' on 'cogni01' succeeded

[root@cogni01 disks]# ps -ef |grep pmon

oracle    5422     1  0 13:12 ?        00:00:00 asm_pmon_+ASM1

oracle    6442     1  0 13:13 ?        00:00:00 mdb_pmon_-MGMTDB

oracle   12510     1  0 13:19 ?        00:00:00 ora_pmon_lmnx1

root     22957  4763  0 13:38 pts/0    00:00:00 grep --color=auto pmon

[root@cogni01 disks]#

[root@cogni01 disks]#

[root@cogni01 disks]# crsctl modify res ora.crf -attr ENABLED=0 -init

[root@cogni01 disks]# crsctl status res ora.crf -init

NAME=ora.crf

TYPE=ora.crf.type

TARGET=OFFLINE

STATE=OFFLINE

[root@cogni01 disks]# cd $ORACLE_HOME/bin

[root@cogni01 bin]# dbca -silent -deleteDatabase -sourceDB -MGMTDB

DBCA cannot be run as root.

[root@cogni01 bin]# su - oracle

Last login: Sun Jun 20 13:34:32 IST 2021

[oracle@cogni01 ~]$

[oracle@cogni01 ~]$ . oraenv

ORACLE_SID = [cdbrac1] ? +ASM1

The Oracle base remains unchanged with value /u01/app/oracle

[oracle@cogni01 ~]$ cd $ORACLE_HOME/bin

[oracle@cogni01 bin]$ dbca -silent -deleteDatabase -sourceDB -MGMTDB

Connecting to database

4% complete

9% complete

14% complete

19% complete

23% complete

28% complete

47% complete

Updating network configuration files

52% complete

Deleting instance and datafiles

76% complete

100% complete

Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/_mgmtdb.log" for further details.

[oracle@cogni01 bin]$ ps -ef |grep pmon

oracle    5422     1  0 13:12 ?        00:00:00 asm_pmon_+ASM1

oracle   12510     1  0 13:19 ?        00:00:00 ora_pmon_lmnx1

oracle   20663 30781  0 13:46 pts/0    00:00:00 grep --color=auto pmon

[oracle@cogni01 bin]$