Howtogeek shows you how to use the Windows 8 Storage Spaces to Mirror & Combine Drives
“Storage Spaces” is a new feature in Windows 8 that can combine multiple hard drives into a single virtual drive. It can mirror data across multiple drives for redundancy or combine multiple physical drives into a single pool of storage.How to Use Windows 8's Storage Spaces to Mirror & Combine Drives
You can even create pools of storage larger than the amount of physical storage space you have available. When the physical storage fills up, you can plug in another drive and take advantage of it with no additional configuration required. Storage Spaces is similar to RAID or LVM on Linux.