Troubleshoot caching and content issues

Available in Classic and VPC

You might run into the following problems when using Global CDN. Find out causes and possible solutions.

Troubleshoot previous image-displayed issues even after image changes

I've changed the image, but the previous image continues to be displayed.

Cause

If the image cached in the Global CDN server is not renewed to the changed image, the previous image may continue to be displayed.

Solution

To delete the content remaining in the cache and renew to the latest content immediately, follow these steps:

1. From the NAVER Cloud Platform console, navigate to > Services > Content Delivery > Global CDN.
2. Click Purge.
3. If the same issue occurs even after you perform a purge, delete temporary Internet files on web browsers.
   • To use web cache services effectively, it is recommended to change the name of the edited content before uploading it.

Troubleshoot content caching unavailable issues

The content is not cached.

Cause

The response header of the common origin server is as follows:

HTTP/1.1 200 OK Content-Length : 61246311 Content-Type : video/mp4 Last-Modified : Thu, 20 Apr 2017 08:43:38 GMT ETag : "f4240-5160656c3c3d2" Accept-Ranges: bytes Server: Apache Date : Tue, 15 Dec 2015 02:50:23 GMT  

You need Content-Length and Last-Modified in the Global CDN server. If you don't have either of them, the Global CDN server cannot provide efficient caching, which the requests to the origin server may increase.
Despite the content that can be cached, if the origin server response has the Set-Cookie header, or the Cache-Control header has settings such as private, no-cache, max-age=0, the content is not cached.

Solution

• Check whether both Content-Length and Last-Modified are set.
• Check whether the origin server response has the Set-Cookie header, or whether the Cache-Control header has private, no-cache, max-age=0 settings.

Troubleshoot continued request issues after applying Global CDN

I've already applied Global CDN, but the origin server receives continued requests.

Cause and solution

In the early phase of applying Global CDN, there is not much content that is cached on Global CDN servers, so a large amount of requests may be temporarily flowing into the origin server. As time goes by, the cached content increases, so requests to the origin server gradually decrease.

Troubleshoot continued request issues to the origin server although the set Cache Expiry time has not passed

Although the set time on Cache Expiry has not passed, continued requests flow into the origin server.

Cause and solution

Global CDN receives requests from cache servers distributed worldwide. So, if you provide the service to various areas, the request volume to the origin server may increase. Also, if Cache Hit is low, caching is excluded from the cache server before the cache expiry expires, so requests to the origin server may flow in continuously.
If requests keep flowing in from the same cache server IP to the origin server, contact Customer Support.