If performing data recovery on a single failed hard disk drive is delicate work, then RAID data recovery is like brain surgery—one wrong move and you could wipe out gigabytes of precious data. It goes without saying that data recovery from a failed RAID isn’t work well-suited to the reckless. But if you can’t afford to pay a professional data recovery lab, then there are a few do-it-yourself approaches that are less risky. One such RAID data recovery method is to reconstruct the RAID as a virtual device. While not 100% successful, given the right parameters you can often restore some or all of your data with minimal impact to the original disks.

To virtually reconstruct a RAID, you’ll need a few things:

• Enough disk images for the RAID to operate normally. For example, if you are attempting to reconstruct a RAID 1 (mirror) that consisted of two drives, you’ll need a valid disk image of at least one drive (granted, you wouldn’t likely need to rebuild a RAID 1 to perform a data recovery, since the data is mirrored across all disks). For a RAID 5 consistent of three disks, you’ll need at least two valid disk images. Choose a program that will create an exact sector-by-sector image of the disk, such as R-Drive Image. If you don’t have enough valid disks to meet this requirement, you may need to repair the disk after imaging it.
• The exact parameters for your RAID configuration. When you rebuild the RAID, you’ll want to recreate the configuration prior to failure. There’s very little, if any, wiggle room for variation from the original RAID configuration. You’ll need to configure your virtual RAID with the exact block size, block order and offset as the physical RAID that your disk images previously operated in. If you are off, then you may see filenames but the files themselves will be corrupted. Or the virtual RAID volume will be unmountable altogether.
• Data recovery software that supports RAID reconstruction. While most free data recovery utilities won’t support RAID reconstruction, there are a few commercial and professional products that do. Using a RAID reconstruction module, you can create a virtual device that can be read like any other logical disk. If successful, the virtual RAID will be mounted and ready to be scanned for data.

Once you have all of the above, the basic steps for rebuilding a RAID are fairly simple. While the actual steps will vary depending on the software you use, the basic process is the same:

1. Launch the data recovery utility and ensure that your disk images are mounted and visible.
2. Create a virtual RAID block. This will pull up a blank block order table.
3. Drag and drop or otherwise configure the disk images into the block order table
4. Specify the block order and offset. These parameters will vary depending on your RAID type. For example, for RAID 1 and RAID 0, you can choose the default or custom. But for RAID 5, you can choose left asynchronous, left synchronous, right asynchronous, right synchronous or custom.
5. Mount the virtual RAID. From here, you can scan the volume for files as you would any other disk. However, you won’t usually be able to write any new data to it.

The key to a successful virtual RAID reconstruction is having all of the pieces of the puzzle in order to put them back together. If you are missing any of the above, your job will be significantly more difficult. If there is extensive damage to your RAID, your only option may be to send it to a data recovery lab for manual "destriping", which can be very costly.