# LinuxCzar

Engineering Software, Linux, and Observability. The website of Jack Neely.

# Monitorama PDX 2023: Finding Π in Observability

July 1, 2023

Its been a long time since I’ve done a presentation in front of real live people. I was honored to be selected to be a Speaker at Monitorama PDX 2023 that was held last week. I put together a talk on some of the challenges that I, and many others, face in the quest to improve Observability. I wanted to touch on some mathematical concepts that underline choices that I make, and why the Four Golden Signals really matter. I close out this talk with an experiment to do the impossible – to aggregate quantiles together to form larger quantiles. Take a listen to find out what happened.

# Abstract

I find the data in Observability fascinating. In every aspect of an SRE I see problems to solve with data rather than brute force. In fact, all of us in the Observability space are really Data Engineers and Data Scientists in disguise. The only way to fully understand our complex systems is through math and visualizations. Let’s explore the 4 Golden Signals and the math behind why they work well and some tricks to bridging Observability and Business Intelligence.

In this talk I’ll cover each of the 4 Golden Signals and speak to the data engineering tools used for each to give folks a broad platform to discover new math and new techniques for solving their own data problems:

1. Traffic: Counters and Calculus – The Physics Behind why Counters Work.
2. Errors: Counting vs Sampling and the Nyquest-Shannon Theory. Your CPU metrics are wrong and I can prove it.
3. Latency: Timers and Distributions – Why averages are horrible and Anscombe’s Quartet. Understanding Gamma Distributions.
4. Saturation: Percentiles and Pipelines – Visualizing percentiles of data, why we cannot combine percentiles, and the magic of histograms.

Finally, all of us in Observability have been asked at some point to participate in managing the data behind Business Intelligence. Data about the product likely comes from the product itself directly through its telemetry. Often the requirements are high cardinality and high in volume making it difficult to store raw data for months on end to produce accurate BI. We’ll work around the limits of percentiles and show some tricks for extracting events, storing those as summary data, and producing monthly percentile based reports with T-Digests.

# Media

Here is the current link to the recording. Its a deep link into the day’s livestream. Once the videos are edited and posted I’ll upgrade this post to include that much nicer link.