March 20, 2022

Napkin Math #19: Metrics For Your Web Application's Dashboards

In the beginning of the year I was helping readwise.io get some of their observability up to snuff. A few weeks later "What should I monitor?" came up on another call, so I decided to list out the metrics that I expect from a great dashboard:

• Web Backend (e.g. Django, Node, Rails, Go, ..)
  • Response Time p50, p90, p99, sum, avg
  • Throughput by HTTP status
  • Worker Utilization
  • Request Queuing Time
  • Service calls
    • Database(s), caches, internal services, third-party APIs, ..
    • Enqueued jobs are important!
    • [Circuit Breaker tripping][cb] /min
    • Errors, throughput, latency p50, p90, p99
  • Throttling
  • Cache hits and misses %
  • CPU and Memory Utilization
  • Exception counts /min
• Job Backend (e.g. Sidekiq, Celery, Bull, ..)
  • Job Execution Time p50, p90, p99, sum, avg
  • Throughput by Job Status {error, success, retry}
  • Worker Utilization
  • Time in Queue
  • Queue Sizes
    • Don't forget scheduled jobs and retries!
  • Service calls p50, p90, p99, count, by type
  • Throttling
  • CPU and Memory Utilization
  • Exception counts /min

More details about what these all mean in the latest napkin post!

Any favourites of yours missing? Let me know.

P.S. On Thursday night, eastern time, I'll be doing a short talk about napkin math on memory bandwidth.