Thundering Herd
Many clients or workers waking up and retrying at the exact same moment, overwhelming the resource they’re all trying to reach.
A thundering herd happens when a large number of clients are synchronized to act at the same instant — a popular cache key expiring and every request suddenly missing at once, or many clients retrying with the same fixed backoff after an outage clears — and the resulting simultaneous spike overwhelms the very resource (a database, an origin server) that everyone was trying to reach. Jittered backoff (adding randomness to retry timing) and request coalescing are the standard fixes.