In Oracle terminology, which failure describes an abrupt termination of the Oracle instance due to an operating system or hardware failure (for example, power loss)?

Introduction / Context:
Oracle categorizes failures to guide detection and recovery procedures. Understanding the category helps determine whether instance recovery or media recovery is required.

Given Data / Assumptions:

• Failure is caused by OS or hardware outage (e.g., power failure).
• Database files are not necessarily corrupted; the instance stopped unexpectedly.

Concept / Approach:
Instance Failure occurs when the Oracle instance (memory structures and background processes) terminates unexpectedly. On restart, Oracle performs crash (instance) recovery using redo to roll forward and undo to roll back uncommitted work.

Step-by-Step Solution:

Verification / Alternative check:
Oracle documentation describes SMON performing instance recovery after abnormal termination.

Why Other Options Are Wrong:
Application failure refers to errors in the application code.
Media Failure involves loss/corruption of database files (needs restore/recovery).
Rollback failure is not a standard Oracle failure category.

Common Pitfalls:
Confusing power failure (instance crash) with datafile corruption (media failure); they require different recovery steps.

Final Answer:
Instance Failure