5xx Server Error
In one sentence
A server-side failure: internal error, service unavailable, gateway timeout.
Analogy Mental model
The kitchen is on fire or the power is out. Customers cannot get in and neither can the scout.
In practice What you actually do
Monitor uptime externally, size the server for peak rather than average, and put a CDN in front so static traffic never reaches the origin. During planned maintenance, return 503 with a retry-after header rather than letting requests time out.
Where people get burned Pitfalls
Repeated 5xx responses teach the crawler to slow down, and sustained failure can remove pages from the index. Recovery is not automatic; it waits for the site to prove it is stable again.
This entry was written in English from the Chinese original, not machine-translated. Read the Chinese version →