Uh, that isn&#x27;t the &quot;O-Ring Theory&quot; I would have expected.<p>The Challenger failed because, while the O-Rings were within tolerances, they shouldn&#x27;t have been varying <i>at all</i>.  So because they were varying unexpectedly, they inevitably failed.<p>I would claim the corresponding devops theory is &quot;measure everything, know what is measurement noise and what is user activity, and eliminate everything else before it causes an outage&quot;.<p>(from Wikipedia: &quot;In one example, early tests resulted in some of the booster rocket&#x27;s O-rings burning a third of the way through. These O-rings provided the gas-tight seal needed between the vertically stacked cylindrical sections that made up the solid fuel booster. NASA managers recorded this result as demonstrating that the O-rings had a &quot;safety factor&quot; of 3. Feynman incredulously explains the magnitude of this error: a &quot;safety factor&quot; refers to the practice of building an object to be capable of withstanding more force than the force to which it will conceivably be subjected. To paraphrase Feynman&#x27;s example, if engineers built a bridge that could bear 3,000 pounds without any damage, even though it was never expected to bear more than 1,000 pounds in practice, the safety factor would be 3. If a 1,000 pound truck drove across the bridge and it cracked at all, even just a third of the way through a beam, the safety factor is now zero: the bridge is defective.&quot;)