As others stated, you have a domain based DFS namespace configured.
If you log into
box1 and go to Admin Tools in the Control Panel, there should be the DFS Management MMC console. This is where you would manage the Domain Based DFS.
There are 2 main components to consider: the Namespace, and Replication.
The namespace (i.e.
share1) in a domain based DFS config is hosted by one or more servers. You could have multiple namespaces (you could add
Share2) and you can have subfolders (Folder Targets) within a namespace (i.e. \mydomain\share1\Marketing & \mydomain\share1\Sales). The folder target creates a virtual path to an actual share path on a server. So for \mydomain\share1\Marketing, the data may be actually at \box1\share\marketing. You could add additional servers as folder targets. so \mydomain\share1\Marketing could point to both \box1\share\marketing & \box2\share\marketing.
Your namespace is likely hosted on
box1. You can find out in the DFS console by expanding "Namespaces", clicking on "share1" and then switching to the "Namespace Servers" tab.
You can also configure data replication between servers for a Folder Target (\Marketing).
If you want more information on setting up the replication check out the Step by Step Guide.
To move the location of the share you just need to add the new server with more capacity in as a folder target for
share1 in the DFS Console.
You could set the new target to replicate the data over from the first, then when the replication is up to date, remove the old server as a folder target.
If your namespace is hosted on
box1 you would want to add the new server in as a namespace server before removing
box1 as a folder target / namespace server. Otherwise your clients will not be able to access the DFS paths.