I'm currently looking to upgrade our Windows Server 2012, which is used as a file server, to Windows Server 2025. I'm trying to figure out the best approach for this upgrade. Should I set up a new virtual machine or just upgrade the existing one? If I go with a new VM, what's the most effective way to transfer the files? We only have one host and no fancy storage solutions. Any advice would be greatly appreciated!
9 Answers
Windows Server 2025 has a built-in file server migration tool in the Admin Center that works effectively. You can check out the official Microsoft documentation for more details on how to use this tool.
For shares on the C: drive, create a new volume on the existing server, move them using Robocopy while preserving permissions, and then share them from the new location. Just remember to back up the share permissions from the registry before you start the migration for ease of setup on the new server.
You have a few options here: Spin up a new VM and use the built-in migration wizard from 2019, which will transfer data and shares. Or, create a new server, export share info, detach the data disk from the old server, and then reattach it to the new server. You can also go the Robocopy route and import share info afterwards.
I recommend against upgrading if you can help it. If all your data is on a separate VMDK or VHDX, just move it to the new server and export/import your registry shares. Consider using DFS too; it's great if you're already set up with it, but the first two methods are more user-friendly if you're not familiar with DFS.
If your data is stored on a separate VMDK or VHDX, then you can detach it from the old VM and attach it to the new one. You can migrate share permissions directly from the registry as well. Upgrading in place is also an option if you prefer not to mess with VMs.
It's often easier to spin up a new server and set up the file share with the same permissions as the old one. You can then use Robocopy to transfer all files and folders, which preserves NTFS permissions. If you want to upgrade in stages, you could do a two-step upgrade: first from 2012 to 2019, then to 2025.
But why bother with Robocopy when you can just attach the disk from the old VM to the new one and re-share it?
Upgrading to 2019 and leaving it there isn't a bad plan unless you really need 2025's features.
For a straightforward solution, here’s my VHD migration method: Create a new Windows Server 2025 VM on the same host, shut down the old server, and attach the existing VHD file to the new one. Just make sure to assign the same drive letter so you won’t need to change policy or drive mappings. Renaming the new server to match the old one can minimize issues too, but it's a one-way path.
Another option is to use a DNS alias to simplify the transition!
Spinning up a new server and using DFS to migrate files to it is also a solid option!
I've done this a bunch of times! I generally spin up a new VM and use Robocopy to move files over in smaller batches to make it manageable. I usually do this during working hours without any major interruptions by using the pull method, where the new server does the heavy lifting by pulling from the old one while it’s still active.
This is definitely a solid approach, as long as it’s feasible.