Downgrade GI from 19c to 12.1 in an Oracle RAC
Downgrade Grid Infrastructure from 19c Grid to 12.1 on Oracle RAC environment.
1) run below 2 commands on both the nodes using grid user
| — crsctl query crs activeversion — crsctl query crs softwareversion |
2) check MGMT DB status on both the nodes
| — srvctl status mgmtdb |
3) delete the mgmtdb though it is not running.
| –From 19C home run below command on first node. ./dbca -silent -deleteDatabase -sourceDB -MGMTDB |
4) Run the downgrade command
| –pls run below command from root user /grid/app/oracle/19.3/grid/crs/install/rootcrs.sh -downgrade |
5) repeat step 3 & 4 on second node
6)start the cluster from old grid home i.e, 12C
| — start clsuter from root user on both the nodes –/u01/app/12.1.0/grid . oraenv +ASM1 # crsctl start crs . oraenv +ASM2 –/u01/app/12.1.0/grid # crsctl start crs |
7) check cluster resource status on both the nodes
| — crsctl stat res -t |
8) need to delete 19 grid_home from Active Cluster Inventory.
| — This needs to be run from only one node and 19c home. –/u01/app/19.0.0/grid/bin /grid/app/oracle/19.3/grid/oui/bin/runInstaller -nowait -waitforcompletion -ignoreSysPrereqs -updateNodeList -silent CRS=false ORACLE_HOME=/grid/app/oracle/19.0.0/grid “CLUSTER_NODES=ORASRVR1,ORASRVR2” -doNotUpdateNodeList |
9) Now update the Active Cluster Inventory with 12c home.
| –/u01/app/12.1.0/grid /u01/app/12.1.0/grid/oui/bin/runInstaller -nowait -waitforcompletion -ignoreSysPrereqs -updateNodeList -silent CRS=true ORACLE_HOME=/u01/app/12.1.0/grid “CLUSTER_NODES=ORASRVR1,ORASRVR2” |
10) Stop ora.crf resource from both nodes and disable it so that it doesn’t start automatically.
| –/u01/app/12.1.0/grid crsctl stop resource ora.crf -ini |
11) Let’s remove mgmtdb Service from Cluster
| srvctl remove mgmtdb |
12) Let’s compare both the clusters now.
| run below two commands on 2 nodes. –/u01/app/12.1.0/grid crsctl query crs softwareversion crsctl query crs softwareversion |
See Also: