How to perform data Synchronize (non-database Synchronize) between two servers?

recently contacted more than one server, there are some problems.

one server An is in Hangzhou and one server B is in the United States. With cdn, overseas users can access server B and domestic users can access server A. For example, users have to upload a picture to the server, then domestic users upload the picture to A, foreign users upload the picture to B, and one day the user goes to the United States from China or, on the contrary, from the United States, the server he visits will change, and the current server does not have the pictures he uploaded before.

because I still have a superficial understanding, I don"t know if the cdn service has the function of automatically Synchronize multiple ip data. I would like to ask how to solve the above problem? Do you want to do Synchronize manually or what?

Nginx linux Server

May.31,2021

pictures are uploaded to Aliyun oss or Qiniu and so on.

the simpler method is not to use Synchronize. When a user requests a resource from server B, A will only send the corresponding resource cash at this time.

pictures are all read and written from C

origin server can actively push the content to multiple CDN nodes.
generally uses CDN back-to-origin.

this kind of resource Synchronize generally needs a good CDN as the resource storage bed.
there is a Synchronize delay problem in other ways.

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