Name the modeled failure
Synthetic failure removes every copy in one power domain. C1 and C2 both use power P; C3 uses power Q. Copies are otherwise usable and no other dependency is modeled. Local requirement: at least one usable copy after either P or Q fails. This is a conditional model, not proof of real infrastructure independence.
| Copy | Power domain | Failure removes it |
|---|---|---|
| C1 | P | P |
| C2 | P | P |
| C3 | Q | Q |
Group copies by domain
- Choose one failing domain
- Remove all its copies
- Repeat for every modeled domain
A copy with an unknown domain cannot demonstrate independent survival.
How many survive each failure, and does the set pass?
Show the worked answer
P failure leaves C3, one copy; Q failure leaves C1/C2, two. The full set passes the one-copy condition. C1/C2 alone would leave zero after P failure.
Count survivors, not labels
| Case | Decision | Reason |
|---|---|---|
| C1+C2 only | Fail | Shared P removes both |
| C1+C2+C3 | Pass model | Minimum survivor count 1 |
Use the power-domain field as a question for actual infrastructure evidence. Three copy names alone do not establish three failure domains.