ORA-00210 Recover system from loss of a Standby Control File

Procedure:

Oracle allow multiplexing of standby control files. Check Parameter Control_Files to get the exact of control file

SQL> SHOW PARAMETER CONTROL_FILES
NAME                                 TYPE        VALUE
 ------------------------------------ ----------- ------------------------------
control_files                        string      /oracle/<SID>/sapdata1/cntrl/cntrl<sid>.dbf,

                                                 /oracle/<SID>/origlogA/cntrl/cntrl<sid>.dbf,

                                                 /oracle/<SID>/origlogB/cntrl/cntrl<sid>.dbf

if one of the multiplexed standby control files is lost or not accessible or all three stand by control file has been lost.Following error occurred in alert.log

ORA-00210: cannot open the specified controlfile
ORA-00202: controlfile: '/oracle/<SID>/sapdata1/cntrl/cntrl<sid>.dbf'
ORA-27041: unable to open file

If only one file has been lost.You can copy an intact copy of the control file over the lost copy

oracle > cp -rp /oracle/<SID>/origlogA/cntrl/cntrl<sid>.dbf /oracle/<SID>/sapdata1/cntrl/

SQL > startup mount;

SQL > ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

If all the files has been then generate the standby file from primary and copy it to the  standby

Primary

SQL > alter database begin backup;

SQL > alter database create standby controlfile as '/oracle/<SID>/<SID>_CNTRL_NEW.dbf' reuse;

Move and rename created standby file to Standby database

Standby

SQL > startup mount;
SQL > ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;