Amazon Dynamo: a shopping cart that never says no

What you'll be able to do

1. 1Choose W and R for a Ledger table from its read / write mix and how much staleness and downtime it tolerates — fast reads, fast writes or balanced.
2. 2Predict whether a read can miss the latest confirmed write from N, W and R, and how many copies can be down before writes or reads fail.
3. 3Explain why W + R > N still isn't linearizable — sloppy quorums, concurrent writes settled by timestamps, a failed write left on some copies — and how hinted handoff, read repair and anti-entropy bring copies back together.

Inside the lesson

steps

5

questions

5

simulation

1

You guess first, then run the system and see if you were right.

Step 1 · The setup