Internt lagrer Kafka data som en append-only log på disk (organisert i segmenter), bruker effektive I/O-teknikker, og administrerer kluster-metadata via ZooKeeper (historisk) eller KRaft (nå). Å forstå internals utdyper forståelsen av Kafkas oppførsel og ytelse.
Lagringen av commit log
Each partition is an append-only LOG stored on disk, split into SEGMENTS (files):
→ new events are APPENDED to the end (sequential writes → fast)
→ events are immutable once written; identified by OFFSET
→ old segments are deleted (retention) or compacted
→ an INDEX maps offsets to file positions (fast lookups)
→ the append-only log is the core of Kafka's design (durable, sequential, efficient)
