Today we have a site collection (with lots of subsites) on SharePoint On Premise, but we would like to migrate the contents to SharePoint Online and adopt the flat architecture that is now recommended. This means that we will get lots of site collections, and the idea is to hold them together as an intranet using a hub site.
We are using Document ID in our SharePoint On Premise site collection, and my plan is to keep the existing Document IDs on all the documents that I migrate. Creating new document IDs would really cause a real mess. I am hoping that a redirect of the SharePoint On Premise site collection to the SharePoint Online hub site (collection) would make it possible for the users to find the documents in the site (collections) connected to the hub, if they click on an URL which points to a document ID. Does anyone know if this is the case? Can documents be located looking up Document IDs via the hub site?
Then there is also the question how to set up Document ID on the new site collections. Since the Document IDs are connected to the site collection, I have to set it up separately at each site collection connected to the hub. I cannot use the same prefix for all site collections, because then I believe the numbers will be duplicated (will be a problem if documents are searched via hub site). One idea to keep everything together a bit would be to have the same prefix + a unique number for the Document IDs of each site collection. Is that a good idea or can it be done in a better way?