A short-lived copy of the backend answer served from disk.

nginx proxy cache balances stale and fresh

An nginx proxy cache has several independent decisions: identifying the stored response, deciding whether it may be reused, deciding whether a new response may be stored, and handling an expired copy. Treating those decisions as one TTL setting makes failures difficult to explain. Verify the resulting request path and bytes, not merely that nginx accepts the configuration. ...

June 24, 2027 · 6 min · XB Field Notes