Serving stale content lets Dynamic Content Delivery Network (DCDN) continue to serve expired static content if your origin server is unreachable or is returning HTTP status code 4xx or 5xx. This improves the availability and responsiveness of your website and ensures smooth experiences for your end users. You do not need to enable this feature for dynamic requests.
How it works
Scenarios
The origin server is unreachable due to server downtime, network interruption, or program errors. In this case, DCDN points of presence (POPs) cannot fetch fresh content from the origin.
Serve Stale Content not enabled: The POP requests to fetch the latest content from the origin. However, the request fails because the origin cannot be reached. Then, the user fails to access your website.
Serve Stale Content enabled: DCDN responds the user with stale content if the origin is unreachable, ensuring the availability of your website.
Procedure
Log on to the DCDN console.
In the left-side navigation pane, click Domain Names.
On the Domain Names page, find the domain name that you want to manage and click Configure.
In the left-side navigation tree of the domain name, click Caching.
Click the Serve Stale Content tab and click Modify Configuration.
In the Serve Stale Content dialog box, set the parameters as needed.
Parameter
Required
Default value
Description
Honor Origin
No
Disabled. In this case, DCDN serves the stale content for the time specified by Stale TTL.
If you enable Honor Origin, and Cache-Control: stale-if-error=xx is included in the response from the origin server, DCDN serves the stale content for the time specified by stale-if-error.
HTTP Status Code on Origin Failure
No
5xx
The status code returned when the origin is unreachable. You can enter 4xx or 5xx for fuzzy match, or exact status codes such as 502 or 504.
Separate multiple status codes with commas (,).
Stale TTL
No
3600 (1 hour)
How long DCDN can serve the stale content if the origin is unreachable. Unit: seconds. Minimum value: 1.
Click OK.