Internamente, o Kafka armazena dados como um log somente de adição em disco (organizado em segmentos), usa técnicas eficientes de E/S e gerencia metadados do cluster via ZooKeeper (historicamente) ou KRaft (agora). Entender os internals aprofunda a compreensão do comportamento e desempenho do Kafka.
O armazenamento de log de commit
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)
