One of the greatest features of Windows Home Server is its dead simple data management and replication, or what they call Drive Extender. Aside from simplicity, Drive Extender has a few storage features that you cannot find with other solutions. In fact, many enthusiasts choose to run WHS instead of Linux or full blown Windows server upwards of 20Tb for this reason.
No drive letters
In WHS you can forget about worrying about filling up individual drives and having to move files to other drives because they are too big to fit. As far as Windows Home Server is concerned your disks are combined to form a single storage pool. This is like a JBOD “just a bunch of disks” array where you have a single namespace to access the data and the disks are spanned together and appear to the end user as one giant disk. This also greatly simplifies your file access as you will not have to navigate to different drive letters to find your files, they can all be accessed via a single shared folder.
Unlike a RAID array which has a variety of restrictions, with WHS you can add any size/type of disk into this array without losing/wasting data if all of the drives are not of equal capacity. If you have a 250Gb IDE , 750Gb SATA, and a 1Tb firewire drive, you can attach all of these devices to your WHS and have 2Tb of seamless storage.
Simple to add/remove storage
If you are filling your your WHS and need to add in another disk, you can just order any new hard drive and pop it into the system. The computer will recognize it and you just have to add the drive to the storage pool. WHS will take care of distributing your files onto this drive in order to balance out the other disks.
Windows Home Server allows you to select certain files that you want to duplicate (in case of a drive failure). Enabling this option automatically creates a copy of the selected files and ensures that at any point in time they are stored on 2 separate hard drives. That way if one of your drives was to fail, you would be sure to not lose this data. If you wanted this sort of protection you would have to use RAID and live with its restrictions/limitations or try and manage the storage and file locations manually which would be a big hastle.
Note: This is however not instead of backing up your data.