Detach diskgroup from 12c GI and attach to 19c GI

Task:

We have two separate Real Application Clusters, one 12c and another 19c. We decided to migrate data from 12c to 19c by simply detaching all ASM disks from the source and attaching to the destination.

Steps:

1. Connect to the 12c GI via grid user and dismount FRA diskgroup on all nodes:

[grid@rac1 ~]$ sqlplus  / as sysasm
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SQL> alter diskgroup FRA dismount;
Diskgroup altered. 

[grid@rac2 ~]$ sqlplus  / as sysasm
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SQL> alter diskgroup FRA dismount;
Diskgroup altered.

You can also use srvctl to stop the diskgroup with one command.

2. Detach disks belonging to the specific diskgroup from 12c cluster and attach to 19c cluster.

3. After ASM disks are visible on 19c cluster, connect as sysasm via grid user and mount the diskgroup:

# Check that there is no FRA resource registered with CRS:

[root@rac1 ~]# crsctl status res -t |grep FRA

# Mount the diskgroup on all nodes

[grid@rac1 ~]$ sqlplus / as sysasm
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> alter diskgroup FRA mount;
Diskgroup altered.

[grid@rac2 ~]$ sqlplus / as sysasm
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> alter diskgroup FRA mount;
Diskgroup altered.

# FRA diskgroup resource will automatically be registered with CRS:

[root@rac1 ~]# crsctl status res -t |grep FRA
ora.FRA.dg(ora.asmgroup)

And data will be there…