Information Safety

Improving technology through lessons from safety.

SIRAcon 2023

As I’ve been posting, I’m cataloging and posting my past presentations, and this is the last one! This talk from SIRAcon 2023 summarizes my experiences leading Site Reliability Engineering (SRE), “Measuring and Communicating Availability Risk”.

The particular focus of my SRE work was on measuring availability and availability risk, and I learned quite a bit over the 3 years or so I did SRE. One of the key lessons was that the value of measuring availability using Service Level Objectives (SLOs) was for decision support (SIRA helped with this framing). That is, SLOs and the associated measurements help make decisions about what to do, either during an incident, tactically over the course of a month, and strategically over the course of several months and into the future.

Our biggest success was the result of measuring availability in ways that supported all three timescales, using a explicitly defined customer-focused measure of “available”, we were able to construct visualizations that helped during incidents (real-time), during maintenance planning (one month), and for longer-term work (many months).

A key element of this success was the business imperative: the work supported a large and important client, who had just negotiated a significant increase in availability by no longer allowing us to count scheduled downtime against our availability target. The Service Level Indictor (SLI) we created helped our incident responders understand outages better, and the SLO we created allowed our teams to schedule maintenance with confidence or confidently defer it. A hidden benefit was that the metrics, being based on direct observations from our monitoring tools, brought together and aligned the different stakeholders on a common view of how available our systems were - the new approach we developed was even adopted by our client as an improvement.

A copy of my slides are here, and the visual notes from the talk are below! As a bonus, you’ll get to see a photo of my dog, Gertie, which was added at the last minute as part of an ongoing cats vs dogs competition at the conference.

visual notes