Clock Skew
The difference in time readings between clocks on different machines. Physical clocks drift; NTP helps but can't guarantee perfect sync. Why distributed systems use logical clocks.
What is Clock Skew?
The difference in time readings between clocks on different machines. Physical clocks drift; NTP helps but can't guarantee perfect sync. Why distributed systems use logical clocks.
Clock Skew is a advanced concept that sits in the Distributed Systems Core area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Clock Skew" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
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Related glossary terms you might want to look up next.
Lamport Timestamp
A simple logical clock where each event increments a counter. If event A causes event B, A's timestamp is always less than B's. The foundation of logical time in distributed systems.
Vector Clock
A logical clock that tracks causality across distributed nodes using a vector of counters. Each node increments its own counter and merges vectors on message receipt.
Distributed Lock
A lock that coordinates access to a shared resource across multiple machines. Implemented via Redis (Redlock), ZooKeeper, or etcd. Much harder than local locks.