Right-sizing
The biggest line on Pixel's bill is four xlarge photo servers that are only about a quarter busy at their busiest. How small can they go before the evening breaks them?
13 minMediumStation: Right-sizingMembers lesson
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- Photo requestsUsers
- Photo API (4 × xlarge)Web API
What you'll be able to do
- 1Predict a server's utilization and monthly price one and two sizes down, and whether the smaller size still carries the peak with headroom.
- 2Explain why a resize decision needs the peak (a high percentile over days), memory as well as CPU, and a target utilization below 100%.
- 3Choose between downsizing, shutting down an idle resource, deleting an orphaned one, or leaving a size alone — and name the risk of each.
Inside the lesson
- steps
- 12
- questions
- 7
- simulations
- 4
You guess first, then run the system and see if you were right.
Step 1 · The setup
Six months on, Pixel has grown — and so has the bill. Its biggest line is now the photo API: four xlarge servers at $0.184 an hour each — about $537 a month. Someone picked xlarge at launch, "to be safe", and nobody has looked since.
Watch one day. In the daytime the API gets 100 photo requests a second; for a couple of evening hours (here t = 20 to 29) it gets 400. A server bills for its size, not for how busy it is — so how busy are these four?
Steps 2–12 are for members