I think C D. The database, Oracle Automatic Storage Management (Oracle ASM), the listener, Oracle Clusterware, and other Oracle products or components store all diagnostic data in the ADR. https://docs.oracle.com/database/121/ADMIN/diag.htm#ADMIN11260

yes elcaso34 is correct, options C and D are correct.

A, B - Wrong: The ADR root directory is known as the ADR base. Its location is set by the DIAGNOSTIC_DEST initialization parameter. If this parameter is omitted or left null, the database sets DIAGNOSTIC_DEST upon startup as follows: If environment variable ORACLE_BASE is set, DIAGNOSTIC_DEST is set to SORACLE_BASE. If environment variable ORACLE_BASE is not set, DIAGNOSTIC_DEST is set to SORACLE_HOME/log. C - Correct: For example, in an Oracle Real Application Clusters environment with Oracle ASM, each database instance, Oracle ASM instance, and listener has an ADR home. D - Correct: Oracle Clusterware uses ADR and has its own Oracle home and Oracle base. E - Wrong: The Automatic Diagnostic Repository (ADR) is a directory structure that is stored outside of the database. It is therefore available for problem diagnosis when the database is down. From <https://docs.oracle.com/en/database/oracle/oracle-database/19/admin/diagnosing-and-resolving-problems.html#GUID-951A06EE-DDF7-4C2A-B0BB-B24418BB2E33>

The ADR root directory is known as the ADR base. Its location is set by the DIAGNOSTIC_DEST initialization parameter. If this parameter is omitted or left null, the database sets DIAGNOSTIC_DEST upon startup as follows: If environment variable ORACLE_BASE is set, DIAGNOSTIC_DEST iS set to SORACLE_BASE. If environment variable ORACLE_BASE is not set, DIAGNOSTIC_DEST iS set to SORACLE_HOME/log.

A - false; default value for DIAGNOSTIC_DEST: If $ORACLE_BASE is not set, then derived from ORACLE_BASE as set by the Oracle Universal Installer. If ORACLE_BASE is not set, then $ORACLE_HOME/rdbms/log is used. B - false; see answer A C - true; Beginning with Oracle Database 11g and later releases, Oracle Automatic Storage Management (Oracle ASM), and other Oracle Database products or components store all diagnostic data in the ADR. D - true; Review this content to understand clusterware-specific aspects of how Oracle Clusterware uses ADR. E - false; data are not held inside an Oracle database schema Sources: A, B - Oracle documentation: 1.108 DIAGNOSTIC_DEST C - Oracle documentation: 21.2 Definitions for Oracle Database ADRC D - Oracle documentation: J Troubleshooting Oracle Clusterware

The correct answers are: A, E If this parameter is omitted or left null, then the database sets DIAGNOSTIC_DEST upon startup as follows: If environment variable ORACLE_BASE is set, then DIAGNOSTIC_DEST is set to the directory designated by ORACLE_BASE. If environment variable ORACLE_BASE is not set, then DIAGNOSTIC_DEST is set to ORACLE_HOME/log Following the url indicated by the correct answer of exam topic. We understand this is the same for Oracle 19

By exclusion: A and B are wrong because the default path is ORACLE_HOME/log for this case: The ADR root directory is known as ADR base. Its location is set by the DIAGNOSTIC_DEST initialization parameter. If this parameter is omitted or left null, the database sets DIAGNOSTIC_DEST upon startup as follows: - If environment variable ORACLE_BASE is set, DIAGNOSTIC_DEST is set to the directory designated by ORACLE_BASE. - If environment variable ORACLE_BASE is not set, DIAGNOSTIC_DEST is set to ORACLE_HOME/log. E is wrong because: The Automatic Diagnostic Repository (ADR) is a directory structure that is stored outside of the database. It is therefore available for problem diagnosis when the database is down. ref. https://docs.oracle.com/en/database/oracle/oracle-database/12.2/admin/managing-diagnostic-data.html#GUID-C78CCAD4-732B-4B14-9C6B-D47AC2A99E30

answer is CD

answer is C and D

I think A D