ORA-16789: standby redo logs configured incorrectly

Creating standby redo log files is a recommended way of configuring dataguard in Oracle database environment. If there is any discrepancy found in standby redo log configuration, you might face ORA-16789 warning. While checking status of dataguard configuration through DGMGRL command, following is that you might see as an example, in a dataguard broker configuration.

[oracle:proddbhost oracle_install]$ dgmgrl / DGMGRL for Linux: Release 19.0.0.0.0 - Production on Tue Jun 6 03:41:19 2023 Version 19.18.0.0.0   Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.   Welcome to DGMGRL, type "help" for information. Connected to "PROD_DB" Connected as SYSDG. DGMGRL> show configuration   Configuration - PROD_DB   Protection Mode: MaxPerformance   Members:   PROD_DB - Primary database     Warning: ORA-16789: standby redo logs configured incorrectly       DR_DB - Physical standby database   Fast-Start Failover:  Disabled   Configuration Status: WARNING   (status updated 53 seconds ago)

For me, the issue was that one of the standby redo log group (single member group) accidentally got created on the local file system of one of the RAC nodes. Of course this redo log file was inaccessible from other RAC node. Therefore, ORA-16789 was being reported. To solve this problem, I dropped the standby redo log group, and recreated on the shared/ASM file system so that both nodes could access it. After that, error was no longer visible.

SQL>  select group#,member from v$logfile where group# in (select group# from v$standby_log);       GROUP# MEMBER ---------- ------------------------------------------------------------          5 +REC/PROD_DB/ONLINELOG/group_5.467.1113444439          6 +REC/PROD_DB/ONLINELOG/group_6.456.1113444455          7 +REC/PROD_DB/ONLINELOG/group_7.465.1113444471          8 +REC/PROD_DB/ONLINELOG/group_8.459.1113444489          9 +REC/PROD_DB/ONLINELOG/group_9.455.1113444507         10 +REC/PROD_DB/ONLINELOG/group_10.458.1113444525         15 /u01/app/oracle/product/19.0.0.0/dbhome_1/dbs/         16 +REC/PROD_DB/ONLINELOG/group_16.490.1116307735         17 +REC/PROD_DB/ONLINELOG/group_17.574.1116307751         18 +REC/PROD_DB/ONLINELOG/group_18.522.1116307769         19 +REC/PROD_DB/ONLINELOG/group_19.546.1116307785         20 +REC/PROD_DB/ONLINELOG/group_20.606.1116307803

Removing group 15 and adding back on +REC ASM diskgroup

SQL> alter database drop standby logfile group 15;   Database altered.   SQL> alter database add standby logfile group 15 '+REC' size 2048m;   Database altered.

Error ORA-1689 is gone.

DGMGRL> show configuration   Configuration - PROD_DB     Protection Mode: MaxPerformance   Members:   PROD_DB - Primary database        DR_DB - Physical standby database   Fast-Start Failover:  Disabled   Configuration Status: WARNING   (status updated 24 seconds ago)