CDN Use
Introduction
CDN (Content Distribution Network) can reduce access to the FDS server. CDN has many nodes deployed in different places. When using CDN, the node will be automatically selected to have a faster effect.
When should I use CDN Prefetch?
If the request is to access FDS resources through the CDN domain name, the hotspot data will be cached on the CDN node according to the CDN cache policy. If the Object to be accessed is not on the CDN, a large number of Objects accessing the CDN at the same time will be returned to the FDS server at the same time, which will bring greater pressure on the FDS server. Therefore, if an Object is accessed simultaneously by a large number of users (such as device firmware), it is best to prefetch the Object to the CDN. Prefetching consumes more FDS/CDN resources. If the Object may not be accessed at the same time, prefetching is not required.
Usage: Click Access Management > Prefetch CDN on the console
When should I use CDN Refresh?
If an Object is overwritten, the previously buffered Object may be hit when accessed through the CDN. Therefore, a CDN refresh operation needs to be performed to update the latest P=Object to the CDN. Like prefetching, refreshing consumes more FDS/CDN resources. If it is not necessary, do not perform this operation frequently.
Usage: Click Access Management > Refresh CDN on the console
We do not provide prefetching and refreshing functionality at overseas sites (access management page is disabled)
The reason is that the CDN used by overseas FDS is cloudfront, and it does not provide prefetch
CDN Caching Policy
The default CDN cache is 1 day. The CDN will consider the cache-related values set by the user in the metadata.
Problem Survey
At some point, I had a problem with the CDN download. Why?
If there is a problem with CDN access, please provide the following information and send it to the responsible engineer according to the feedback template.
- Time the problem occurred
- URL where the problem occurred
- Exit IP and node IP accessed
- The wireshark/tcpdump packet capture log
When the user downloads the file, there is a 302 jump and the file contents are damaged
f your users use http download, please confirm whether operator hijacking has occurred The only way to solve the hijacking is to use https
Why did I still download the old file after using a CDN refresh?
- Confirm by non-CDN method that the new file has been uploaded to the FDS.
- Make sure to click Refresh on CDN on the console after the file has been updated for 5 minutes.
- Delete the local browser cache and wait 5 minutes to reconfirm that the CDN file was downloaded correctly.
- CDN refresh and prefetch are only valid for the CDN domain name listed in the document and will not affect the old CDN domain name