As questions and challenges loom over the tech industry and the larger economy, now is a perfect time for us to take a step back and learn from the past. As reliability engineers, we regularly use Service Level Objectives (SLOs) to understand the performance, reliability, and trends of our systems to help inform and prioritize our decision making.

The outages span the giants of the Internet and some of the biggest failures of IT resilience we were subject to – from AWS’s trifecta of outages in December 2021 to the October ‘21 outage that took down Facebook, Instagram, WhatsApp, and interrelated services. We also look at some more intermittent outages that you may have missed.

Toil. Few other words have the same visceral impact for SREs as their four-letter nemesis: toil. Although pretty much everyone recognizes and agrees that toil is bad, it is a term that is frequently misused in colloquial use. In common English usage, toil is defined as “long strenuous fatiguing labor”. As a term of art in the SRE profession, “toil” has several very specific characteristics which distinguish it from other sorts of work which people spend time on.