I have a server with two Raids.
Raid 0: 2x 1TB
Raid 6: 8x 2TB
The first raid I used for the hyper-v installation itself. The virtual machines should use the Raid 6, but how can I config it?
I need at least one file server with the most of the disc space (maybe a second). But every vhd has a maximum of 2 TB and I can't use the volume directly because other virtual machines have to have access the Raid6.
What do I do?
Add multiple 2tb vhds to your fileserver vm.
Inside the fileserver vm use disk manager to setup disk spanning to create one huge partition.
It's difficult to understand your question, but you can store VHDs on any volume on the system. Either check the box that says "Store VHD in a different location" when you're creating the VM, and then choose where you want to store it... or, click "Hyper-V Settings" in the action pane on the right to configure it permanently.
Windows 2008 R2 Hyper-V supports VHDs of up to 2TB. Period. If you need VHDs that are bigger than 2TB, then you are going to have to wait until Windows Server 2012, where the limit will be bumped to 64TB per VHD.
edit: One alternative you might consider is making your "file server" VHD a regular size big enough for the OS install, then allow it to access the rest of the volume (several terabytes) as a passthrough disk or something.
http://blogs.technet.com/b/askcore/archive/2008/10/24/configuring-pass-through-disks-in-hyper-v.aspx