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The Always Online option serves stale cached content when the origin is unreachable. CDN checks origin availability on each incoming request and switches back to fresh content as soon as the origin recovers. Stale responses include the X-Cache: Stale header. The following error conditions trigger stale content delivery:
  • error — network or connectivity issue
  • updating — cache is being refreshed
  • Timeout
  • Invalid Header
  • Error 500
  • Error 502
  • Error 503
  • Error 504
  • Error 403
  • Error 404
  • Error 429
When the origin is unavailable, the CDN cache may not contain all assets required for a complete page. Some images, stylesheets, or other static content may be missing.

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Configure Always Online

To configure Always Online via the Gcore Customer Portal: 1. Navigate to CDN resources and click the CDN resource. 2. In the sidebar, click Cache. In the expanded menu, click Always online.
Resource settings with Cache expanded in the sidebar and Always online selected, showing the Enable always online toggle
3. Enable the Enable always online toggle. 4. In the Serve stale cached content in case of the following errors field, select the error codes for which CDN serves stale content. 5. Click Save changes.