Facebook's official story is that yesterday's outage was due to a "server configuration change".
https://twitter.com/facebook/status/1106229690069442560?s=19
According to the house eunuch and CNN Business, it was the biggest interruption ever suffered by FB.
https://twitter.com/brianstelter/status/1106231823431016448?s=19
My thoughts exactly. I work for a very successful company and we have 2 maintenance windows a week and they are in the middle of the night.
FB has systems far more advanced than we have to prevent issues. I call bs on "server maintenance".
https://code.fb.com/production-engineering/making-facebook-self-healing-automating-proactive-rack-maintenance/