-- 首先在集群里停掉2号节点的实例
[oracle@host01 app]$ srvctl stop instance -d racdb -i racdb_2


--查看rac的类型，目前显示为（Type: RAC）
[oracle@host01 app]$ srvctl config database -d racdb
Database unique name: racdb
Database name: racdb
Oracle home: /u01/app/oracle/product/12.1.0/db_1
Oracle user: oracle
Spfile: +DATA/RACDB/PARAMETERFILE/spfile.288.960026421
Password file: +DATA/RACDB/PASSWORD/pwdracdb.276.960026013
Domain: 
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: racdbpool
Disk Groups: FRA,DATA
Mount point paths: 
Services: RACDBACN
Type: RAC
Start concurrency: 
Stop concurrency: 
OSDBA group: dba
OSOPER group: oper
Database instances: 
Configured nodes: 
Database is policy managed


-- 转换成rac one node类型
[oracle@host01 app]$ srvctl convert database -d racdb -c RACONENODE


-- 再查看rac的类型，此时显示（Type: RACOneNode）
[oracle@host01 app]$ srvctl config database -d racdb
Database unique name: racdb
Database name: racdb
Oracle home: /u01/app/oracle/product/12.1.0/db_1
Oracle user: oracle
Spfile: +DATA/RACDB/PARAMETERFILE/spfile.288.960026421
Password file: +DATA/RACDB/PASSWORD/pwdracdb.276.960026013
Domain: 
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: racdbpool
Disk Groups: FRA,DATA
Mount point paths: 
Services: RACDBACN
Type: RACOneNode
Online relocation timeout: 30
Instance name prefix: racdb
Candidate servers: 
OSDBA group: dba
OSOPER group: oper
Database instances: 
Database is policy managed


-- 尝试再重新转换回rac类型
[oracle@host01 app]$ srvctl convert database -d racdb -c RAC


-- 查看rac的类型，已经变成rac了，而且在两个节点上的实例也被起来了
[oracle@host01 app]$ srvctl config database -d racdb
Database unique name: racdb
Database name: racdb
Oracle home: /u01/app/oracle/product/12.1.0/db_1
Oracle user: oracle
Spfile: +DATA/RACDB/PARAMETERFILE/spfile.288.960026421
Password file: +DATA/RACDB/PASSWORD/pwdracdb.276.960026013
Domain: 
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: racdbpool
Disk Groups: FRA,DATA
Mount point paths: 
Services: RACDBACN
Type: RAC
Start concurrency: 
Stop concurrency: 
OSDBA group: dba
OSOPER group: oper
Database instances: 
Configured nodes: 
Database is policy managed


-- 再重新转换回rac one node
[oracle@host01 app]$ srvctl convert database -d racdb -c RACONENODE
PRCD-1154 : Failed to convert the configuration of cluster database racdb into its equivalent RAC One Node database configuration because cluster database is running on more than one server [host02, host01]


-- 提示有两个节点在跑，关掉2号节点
[oracle@host01 app]$ srvctl stop instance -d racdb -i racdb_2
PRCD-1315 : failed to stop instances for database racdb
PRCR-1014 : Failed to stop resource ora.racdb.db
PRCR-1065 : Failed to stop resource ora.racdb.db
CRS-2529: Unable to act on 'ora.racdb.db' because that would require stopping or relocating 'ora.racdb.racserv.svc', but the force option was not specified


-- 提示要先关掉racserv这个service才能关闭2号节点实例
[oracle@host01 app]$ srvctl stop service -d RACDB -s racserv


-- 再次关闭实例
[oracle@host01 app]$ srvctl stop instance -d racdb -i racdb_2


-- 转换rac至rac one node
[oracle@host01 app]$ srvctl convert database -d racdb -c RACONENODE


-- 查状态，转换成功
[oracle@host01 app]$ srvctl config database -d racdb
Database unique name: racdb
Database name: racdb
Oracle home: /u01/app/oracle/product/12.1.0/db_1
Oracle user: oracle
Spfile: +DATA/RACDB/PARAMETERFILE/spfile.288.960026421
Password file: +DATA/RACDB/PASSWORD/pwdracdb.276.960026013
Domain: 
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: racdbpool
Disk Groups: FRA,DATA
Mount point paths: 
Services: RACDBACN
Type: RACOneNode
Online relocation timeout: 30
Instance name prefix: racdb
Candidate servers: 
OSDBA group: dba
OSOPER group: oper
Database instances: 
Database is policy managed