I analyzed LE uptime at the end of 2017 - looking at its first 16 or so months. As it’s been a while, I was somewhat curious what changed and did another quick analysis of the https://letsencrypt.status.io data to find out.
The exec summary: using only “full disruptions” (including planned restarts of LE services), the uptime is somewhere around 99.92% - compared to 99.86% in 2017.
If we include partial “incidents”, the uptime goes down to 96.4% - while you probably wouldn’t notice some of the partial service disruptions, it’s hard to further categorize those with the available data.
You can see the full text with charts at: https://keychest.net/stories/lets-encrypt-uptime-2-years-on
(please do chip in if you spot any issue with the results!)
My main question - when I sipped a single malt looking at the charts - was what aspirations are there in terms of reliability and if it can ever achieve the uptime of “commercial” CAs.