HyperV and Virtual Hard Drives

Hi, I have a server with MS Server 2012 R2 installed.  It has the HyperV role installed and configured.  I would like to accomplish three things with this server:
1.  Install a virtual machine;
2.  Install a virtual hard disk that supports the operating system;
3.  Install a virtual hard disk that provides storage for the shared files.
I have attempted to complete the above, but I must have made a critical error.   My assumption is that the HyperV process would allocate the hard disk space accordingly, but that did not happen.  The parent server with the MS Server 2012 R2 operating system enabled me to create a virtual machine (running MS Server 2012 R2 OS), and I specified a virtual hard disk with 3.8 terabytes of capacity.  The parent server has four (4) SATA hard drives, each with 1.8 terabytes of capacity.   Two things resulted which have me scratching my head:
a. The virtual harddrive turned out to be the C: drive among the four drives.  The HyperV application did not allocate any space from the other three drives.  
b.  When I attempted to transfer files to the Virtual Machine, it ran out of disk space and locked up.  The amount of files certainly did not equate to 3.8 terabytes nor the amount of available space on the C: drive.
So what did I do incorrectly?  How do I configure the Virtual Machine so that it functions as above?
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Dan CraciunIT ConsultantCommented:
Q: why would it allocate space from the other drives?
It asked you where you want to store the virtual hard disk image, and that was a folder.

If you want to use multiple drives as a single drive, configure a RAID array on the host.

David Johnson, CD, MVPOwnerCommented:
a .vhdx is imply a FILE and you first have to configure the host operating system so that there is enough free space to hold this file. if these drives are blank you can use storage spaces.. create a new storage space and add these drives to the space then intialize/format the storage space drive and when you create the disk set the location.
the locaction is marked in REDhttp://windows.microsoft.com/en-CA/windows-8/storage-spaces-pools

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