• 1 Status
• 2 Top Event
• 3 Minimal Cut Set
• 4 Description
• 5 Severity
• 6 Likelihood
• 7 Mitigation
• 8 Residual Severity
• 9 Residual Likelihood
• 10 Affected Documents
• 11 Monitoring

FTA-001: Disk Failure With Silently Failing Backup ¶

1 Status ¶

2 Top Event ¶

Permanent loss of user data (TOP-1)

3 Minimal Cut Set ¶

{E1, E4} — disk hardware failure while the backup job has been failing silently

4 Description ¶

The primary disk fails, and only then does it surface that the scheduled backup job has been failing for weeks without anyone noticing. Both legs of the AND gate are true and the data is gone for good.

5 Severity ¶

10

6 Likelihood ¶

4

7 Mitigation ¶

Alert the user when a scheduled backup has not completed successfully within its configured period, so a failing backup leg is repaired long before a disk failure can coincide with it.

8 Residual Severity ¶

10

9 Residual Likelihood ¶

2

10 Affected Documents ¶

11 Monitoring ¶

Backup completion alerts are reviewed weekly; a silent gap longer than one period reopens the analysis.