ORA-16086: Redo data cannot be written to the standby redo log

2024-11-22T07:09:14.930561+00:00 Errors in file /data/oracle/MYDB/admin/diag/rdbms/MYDB/MYDB7/trace/MYDB7_lgwr_178713.trc: ORA-16086: Redo data cannot be written to the standby redo log LGWR (PID:178713): Error 16086 for LNO:2 to 'MYDB_sb' LGWR (PID:178713): Failed to archive LNO:2 T-1.S-1765560, error=16086 2024-11-22T07:09:14.945680+00:00 Thread 1 advanced to log sequence 1765560 (LGWR switch), current SCN: 13393654452914 Current log# 2 seq# 1765560 mem# 0: +DATA/MYDB/onlinelog/group_2.471.1046140279 Current log# 2 seq# 1765560 mem# 1: +REC/MYDB/onlinelog/group_2.19611.1046140279 2024-11-22T07:09:16.758563+00:00 ARC1 (PID:184077): Archived Log entry 7135590 added for T-1.S-1765559 ID 0x794f6c68 LAD:1 2024-11-22T07:09:26.011951+00:00

This error message is normally caused by some issue with the standby redo logs on which remote LGWR (from primary) is not able to write. Due to this error, standby becomes out of sync with the primary database. 

In this situation, the fastest solution is to clear the standby redo log groups after disabling the managed recovery. 

If you are using DG Broker, disable DG broker from DGMGRL utility, or alternatively disable from SQLPLUS. Then clear all standby redo log groups. 

SQL> select group# from v$standby_log;     alter database clear logfile group 1;  ...  ...  ...

After you have cleared all standby redo log groups, enable back the managed recovery.