consistency

Large object uploads are a reliability design problem, not a bandwidth one. Parts, retries and the completion call decide whether a flaky link costs one chunk or the whole night.

The design round where the honest answer is mostly about data. Stateless traffic across regions is straightforward; the database is where active-active is either solved or pretended.

CAP is not a menu of two letters per system. The scored answer knows what the theorem claims (narrowly), what most engineers misquote, and what a split-brain costs when both halves accept writes.

Flags sit on the request path of everything, so a slow flag service is a site-wide outage waiting to happen. Local snapshots, propagation numbers, and audit trails are what interviewers dig for.