Mounting unallocated storage in Windows Server 2008
1. If you attach a new disk to your VM, you may not see it straight away in Windows Explorer. To be able to see it, go into the Server Manager. Then Click ‘Storage’ and ‘Disk Management’. You should see the new disk listed there as being offline.
2. Simply right-click and select ‘Online’.
You may have to format the disk if it is a newly created volume.
3. You will now see the disk attached in Windows Explorer
This is a normal datadisk with primary storage. You may be charged for the storage allocated in your account.