This episode of DisasterCast discusses what happens when attempts to make things safer backfire.

by trying to suppress small problems, we create a reservoir of danger waiting to burst out

  Drew Rae

These images offer a glimpse into the visual patterns that appear in our variables and time-series, and the beauty that emerges from chaos. Some of the images in these galleries appeared during difficult rollouts, and some even during production incidents. All come from graphs generated by Google’s monitoring systems.

  Google

The popular slogan says “test in production”, but what if your business simply doesn’t allow it?

For any scenario where I expect to be causing client impact, I’d rather test in non-production than not test at all, since production is clearly off the table.

  Christina Yakomin — InfoQ

There’s been a trend toward narrating our engineering work on company blogs, without which this newsletter probably wouldn’t exist.

  Jordan Teicher — New York Times

My team recently moved databases from local files in the codebase to an online Database.

It didn’t go quite as planned, but they got there in the end.

  Kaustubh Hiware — Mercari

In Product Analytics we wanted to support our colleagues in SRE, so we created a model to predict the monetary costs of incidents affecting our conversion funnel.

  Enrique Hernani Ros — HelloFresh

There’s some interesting detail here about multiple failed UPSes and an accidental voltage mismatch exacerbating the situation.

  Laura Dobberstein — The Register

This article contains:

two reasons why site reliability engineers may be part of IT teams for years to come, and two reasons why site reliability engineering may turn out just to be a fad.

  Christopher Tozzi — ITPro Today

This article proposes an interesting method for incident investigation: constantly try to disprove your hypotheses to avoid confirmation bias.

  Ivan Merill — Fiberplane

How I’ve managed to run this newsletter for almost 7 years without a single mention of the Therac-25 incidents is beyond me. Therac-25 is an important lesson for all of us as we design systems and analyze incidents.

  Adam Fabio — Hackaday

Even though this happened 14 years ago, the cause is very much still relevant today. If you have two bit-flips in the same TCP packet, it’ll still pass the checksum.

  Poppy Linden — Linden Lab

This article proposes two criteria: Actionability and Investigability.

  Dan Slimmon

This incident write-up chronicles an incident in which a poison pill message repeatedly crashed their Heroku app.

  Lawrence Jones — incident.io

Take this one with a grain of salt since there’s a fair bit of counterfactual reasoning in the description. Nevertheless there’s a lot to learn from this and Wikipedia’s article on the same accident.

  Admiral Cloudberg

Incident duration and severity are not related, and we have the in-depth data to prove it.

It’s time for another VOID report! I’m glad this project is still going strong.

  Courtney Nash — Verica

I haven’t been paying attention to the recent attempts to legislate cloud provider reliability, and this article was a great catch-up. There’s a lot going on here.

  Jeff Martens — Metrist

I’m still trying to figure out how I feel about this one, but I’m definitely glad I read it.

  Fred Hebert

FireHydrant published this report with statistics from over 50,000 incidents experienced by their customers.

  FireHydrant

Want to get a solid understanding of how the Linux shells work, including file descriptors, process management, and sessions? This one goes really deep with lots of example programs.

  Viacheslav Biriukov

Check it out, Google search finally has a proper status page!

  Google

It’s one of those “awesome ___” repos on GitHub, this time for resources about writing SLOs.

  Steve Azzopardi (@steveazz)

If you’re going to classify incidents by “root cause”, try these on for size: “production pressure”, “goal conflicts”, and more in this article.

  Lorin Hochstein

Sure, the pilots were engaging in an activity that could be considered dubious. But what’s really worth digging into in this air accident is how surprise may have led them to forget their training on how to recover stable flight.

More on the same accident:

• Wikipedia
• Mentour Pilot

  Admiral Cloudberg

In this interview, Tammy Butow goes into detail on what it’s like being on call and how she improved a team’s horrible on-call burden by a factor of 10.

  Elena Boroda — Fiberplane

Do you need just one or two SREs? Or should you build a sprawling SRE team, with a dozen or more SREs on hand to support your organization’s reliability needs?

  JJ Tang — Rootly
  This article is published by my sponsor, Rootly, but their sponsorship did not influence its inclusion in this issue.

An unsanctioned (but not unheard of) action, a race condition, and multiple known design issues all contributed to this air accident.

  Admiral Cloudberg

A first-hand account of one way to handle DR in this reddit post. Worth reading through to the end.

  u/disasterrecoverywhat — reddit

Rackspace’s Hosted Microsoft Exchange offering has been down for over a week, and they’re assisting (and paying for) customers to move to Microsoft 365.

  Roger Montti — Search Engine Journal

It’s a good idea to leave yourself a safety hatch to administer your system when everthing’s gone to heck… otherwise you might have to break out the angle grinders.

  Oren Eini — Hibernating Rhinos

This intriguing debugging story also sheds some light on how Honeycomb’s custom-built columnar data store works.

  Paul Osman — Honeycomb
  Full disclosure: Honeycomb is my employer.

Tons of incredibly good advice in this infographic + article on debugging.

  Julia Evans