What is annualized failure rate (AFR)?

Annualized failure rate is the projected failure rate for a year. It is the relation between the amount of failed drives of a particular model and their hours in operation per year.  More precisely: 

AFR = (100 * amount of failed drives) / (total power on hours /24/365)

Sources:

• https://www.backblaze.com/blog/hard-drive-reliability-q4-2015/ 

Tags: Drive Failure, Stroage Device