Story
Instagram: 14 million users, 3 engineers
How a tiny team took a photo app to 14 million users a little more than a year after launch — and three scaling problems every fast-growing app hits.
15 minEasyMembers lesson
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What you'll be able to do
- 1Predict per-server load when a load balancer fronts N servers.
- 2Explain why session state must leave the app servers before scaling out.
- 3Spot when adding app servers stops helping because a shared dependency is saturated.
- 4Predict database reads per second from traffic and hit ratio.
- 5Compute how a redundant pair raises availability.
Inside the lesson
- steps
- 5
- questions
- 7
- simulations
- 4
You guess first, then run the system and see if you were right.
Step 1 · The setup
In just over a year Instagram grew to 14 million users — and the system behind it was built and run by three engineers. Their rules were short: keep it very simple, don't reinvent the wheel, use proven technology.
Walk through three problems every fast-growing app hits. Decide what you would do, then see what Instagram was running by late 2011.
Steps 2–5 are for members