Before the cloud, people were trying to reduce the mean time between failure (MTBF) essentially trying to prevent a thing from failing. With cloud, people are trying to recover as quickly as possible (mean time to recovery) accepting that things will fail —- it’s about how fast you can react to it.

John Allspaw (previously CTO at Etsy) has written about this: https://www.kitchensoap.com/2010/11/07/mttr-mtbf-for-most-ty...