Remember an ORA-00210,ORA-00202,ORA-27086 error in the process of building DG.

ORA-00210: cannot open the specified control file

ORA-00202: control file:'/ u01According to an oracle control 01.ctl'

ORA-27086: unable to lock file-already in use

Train of thought:

1. Check whether the two files "lk" and "sgadef.dbf" exist, and delete them if they exist.

2. See if there is a background process.

3. Check whether oracle's shared memory segment and signal set (semaphores) still exist.

Actual operation:

[oracle@linux ~] $cd $ORACLE_HOME/dbs

[oracle@linux dbs] $ls

Hc_SID.dat initdw.ora init.ora lkSID orapwSID spfileSID.ora

[oracle@linux dbs] $rm lkSID

[oracle@linux dbs] $ls

Hc_SID.dat initdw.ora init.ora orapwSID spfileSID.ora

[oracle@linux dbs] $ps-ef | grep ora_ | grep SID

Oracle 4981 1 0 09:00? 00:00:00 ora_pmon_SID

Oracle 4983 1 0 09:00? 00:00:00 ora_psp0_SID

Oracle 4985 1 0 09:00? 00:00:00 ora_mman_SID

Oracle 4987 1 0 09:00? 00:00:00 ora_dbw0_SID

Oracle 4989 1 0 09:00? 00:00:00 ora_lgwr_SID

Oracle 4991 1 0 09:00? 00:00:01 ora_ckpt_SID

Oracle 4993 1 0 09:00? 00:00:01 ora_smon_SID

Oracle 4995 1 0 09:00? 00:00:00 ora_reco_SID

Oracle 4997 1 0 09:00? 00:00:00 ora_cjq0_SID

Oracle 4999 1 0 09:00? 00:00:07 ora_mmon_SID

Oracle 5001 1 0 09:00? 00:00:00 ora_mmnl_SID

Oracle 5003 1 0 09:00? 00:00:00 ora_d000_SID

Oracle 5005 1 0 09:00? 00:00:00 ora_s000_SID

Oracle 5023 1 0 09:00? 00:00:00 ora_qmnc_SID

Oracle 5133 1 0 09:00? 00:00:00 ora_q000_SID

Oracle 5139 1 0 09:00? 00:00:00 ora_q001_SID

Oracle 31755 1 1 13:21? 00:00:00 ora_j000_SID

[oracle@linux dbs] $ps-ef | grep ora_ | grep SID | grep pmon

Oracle 4981 1 0 09:00? 00:00:00 ora_pmon_SID

[oracle@linux dbs] $kill-9 4981

[oracle@linux dbs] $ps-ef | grep ora_ | grep SID | grep pmon

[oracle@linux dbs] $ipcs-m

-Shared Memory Segments-

Key shmid owner perms bytes nattch status

Re-startup the database and solve the problem.