Box Tech Blog » A Tale of Postmortems
august 2014 by jm
How Box introduced COE-style dev/ops outage postmortems, and got them working. This PIE metric sounds really useful to head off the dreaded "it'll all have to come out missus" action item:postmortems action-items outages ops devops pie metrics ranking refactoring prioritisation tech-debt
The picture was getting clearer, and we decided to look into individual postmortems and action items and see what was missing. As it was, action items were wasting away with no owners. Digging deeper, we noticed that many action items entailed massive refactorings or vague requirements like “make system X better” (i.e. tasks that realistically were unlikely to be addressed). At a higher level, postmortem discussions often devolved into theoretical debates without a clear outcome. We needed a way to lower and focus the postmortem bar and a better way to categorize our action items and our technical debt.
Out of this need, PIE (“Probability of recurrence * Impact of recurrence * Ease of addressing”) was born. By ranking each factor from 1 (“low”) to 5 (“high”), PIE provided us with two critical improvements:
1. A way to police our postmortems discussions. I.e. a low probability, low impact, hard to implement solution was unlikely to get prioritized and was better suited to a discussion outside the context of the postmortem. Using this ranking helped deflect almost all theoretical discussions.
2. A straightforward way to prioritize our action items.
What’s better is that once we embraced PIE, we also applied it to existing tech debt work. This was critical because we could now prioritize postmortem action items alongside existing work. Postmortem action items became part of normal operations just like any other high-priority work.
august 2014 by jm
Copy this bookmark: