1. stop the database service.
srvctl stop database -d PROD
2. start the database in mount state.
srvctl start database -d PROD -o mount
3. enable archive log mode.
alter database archivelog;
4. Restart the database service (using srvctl)
srvctl stop database -d PROD
srvctl start database -d PROD
5. set the archive destination to a ASM DISK
SQL> alter system set log_archive_dest_1='LOCATION=+ARCH/' scope=both sid='*';
System altered.
SQL> archive log list
SQL> alter system switch logfile;
System altered.
