Some questions for everyone to google for answers to understand and clarify:

• When a consumer wants to remind from a X offset, how would consumer know what offset represents what data?
• Data is stored on disk and never deleted, so the rewind is possible and offset remains the same for the same data, correct?
• What if data size grows and clean up is required on disk?
• Does kafka uses cache?
• How does kafka writes on disk, like is it a plain file?