I am sorry if I have misunderstood.
Please note that you can use any third-party replication tool including the DFS in order to keep the files on the files system in sync between the environments.
If you would like to exclude any folder from replication, please check the documentation of the replication engine on how you can configure it in order to achieve this. Since this is a third-party engine and it is not related to the Sitefinity functionality, I am afraid I cannot be of much help regarding any detailed steps to achieve this.
I searched over the internet and found the below articles which might be helpful:
It is also important to note that all the configurations should be identical on all nodes. the configurations are stored under the App_Data/Sitefinity/Configuration folder and you need to make sure that the content of this folder is identical on each nodes.
In addition to this, please note that if you store the media content on the files system (not in the database) you also need to make sure that you sync the files under the ~/App_Data/Storage folder. The ~/App_Data/Storage folder is the default folder where Sitefinity stores the binary data for the media content you upload to Sitefinity when the storage provider is set to FileSystem (this is the default file system provider). Sitefinity creates a folder under it with the name of the library and stores the binary data of the images stored under this folder.
If you have any libraries which you have set to use the FileSystem as a storage provider and you have uploaded media content items to this library, you should have folders and files under the Storage folder. You need to make sure that this folder is identical on all environments so that when you upload a media content item (image, document, video) on one node this media item to be available on all nodes.
The same is also valid for the Search folder under ~/App_Data/Sitefinity which should be identical on all servers. Please check the KB article for more details on this: http://www.sitefinity.com/developer-network/knowledge-base/details/different-search-results-on-the-different-nodes-in-load-balanced-environment
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