Blog. Things I learned that were worth keeping.

• Why Raft is easier to explain than PaxosSep 20261 minPaxos is correct and Raft is correct.
• What a write-ahead log actually promisesSep 20261 minA write-ahead log promises one thing: before the table changes, the change is on disk somewhere it can be found again.
• Consistent hashing, from the paper to a hundred linesSep 20261 minConsistent hashing answers a small question with a large consequence: when a node leaves, how many keys have to move?
• Backpropagation without the calculus fogSep 20261 minBackpropagation is the chain rule applied in the sensible order.
• Merkle trees and the art of not comparing everythingSep 20261 minTwo replicas each hold a million blocks. How do you find the three that differ without shipping a million hashes across the network?
• Moving a terabyte without losing a rowSep 20261 minMoving data is easy. Moving data and being able to prove nothing went missing is the actual job.