TFS 2017.3.1 Merge Collections [closed]

We are currently on TFS 2017.3.1 On Prem. We have 1 very large collection and another smaller collection. We would like to move the smaller collection into the larger. We use everything in TFS, code Git and Source Control, work items, builds, releases... Are there any tools/instructions out there for doing such a thing. I saw there was an integration tool, but it is no longer supported. Also of the tools out there is this something that would be break our support with MS. I mean if we merged collections would we still be able to get help from MS with our MSDN's for TFS issues. Is this something that is bound to cause us problems down the road if we do attempt it?

There's no way to do it without significant effort and some amount of data loss (links between work items, for example, are hard to migrate, as are links between work items and commits). Team Project Collections are intended to be completely isolated.

Unless you're directly manipulating your TFS project collection databases, you're unlikely to have a support issue. Use the established APIs and you'll be fine.

None of the tools I've tried do a great job, honestly. The fact that no one has successfully built a tool to do this should give you an idea of how hard it is to do properly.

I'd say you'd be better off doing the following:

Make the "source" TPC read-only. It now exists only as a reference for work items from before the migration.
Move your Git repos (clone, new remote, push)
Move only active work items and test cases (manually or via some REST API scripting, depending on number)
Export/import build and release definitions (again, manually or via REST API scripting).

It's going to be painful.