Each service, hosting provider or online store can face interruptions in operation. Therefore, the server can be unavailable.
We added an option to the control panel which allows delivering of stale cached content when the origin server is unavailable for a long time (longer than CDN content cache expiry time).
Stale content will be delivered with the X-Cache: Stale header in case of the following errors:
- error (network problems)
- timeout
- invalid_header
- updating (cache updating)
- http_500
- http_502
- http_503
- http_504
- http_403
- http_404
- http_429
The origin server availability is checked with each new user request. When the origin server becomes available, CDN caches a fresh version of the file.
The option is enabled by default. You can manage it in the Advanced Settings of CDN resource. In the Cache section, click Add Option and select Always Online.
You can choose the errors for which we will deliver stale content or disable the option.
Attention! When the site is unavailable, CDN cache may have not enough content to display the entire page, so we cannot guarantee that all files will be displayed properly. When user opens a page some images, style sheets, or other static content can be unavailable.