RAID DATA RECOVERY IN SEVERAL STEPS

When a RAID fails, there are certain actions you can take that will make the problem better and other actions you can take that will make the problem worse. In this brief tutorial, we’ll walk through some of the steps that will increase your chances of a successful RAID data recovery.

STEP ONE: DISCONNECT THE RAID MEMBER DISKS		STEP TWO: IMAGE THE DISK
For a hardware RAID, you will want to remove all the disks from the RAID and label them. Label the cables and ports as well, in case you need to physically or virtually reassemble the RAID.		There are two reasons to create an image of the RAID member disks. First, it will allow you to salvage any disks that are failed or failing without causing any further data loss. Second, it will allow you to try different configurations and data recovery methods without corrupting the data on the RAID volume. Forcing a RAID into an invalid configuration can damage the file structure or corrupt the data. To create an image, connect the disk to a non-RAID disk controller, such as a hard drive dock, enclosure or a normal hard drive bay on your computer.
STEP THREE: PREPARE BACKUP MEDIA		STEP FOUR: REBUILD THE RAID FROM THE DISK IMAGES
You should never save recovered data onto the same physical disk that it was recovered from. So, you will need a blank drive that can accommodate the data you want to recover.		Using a professional data recovery tool, use the disk images to build your RAID virtually. Use the same RAID level and parameters that your physical RAID used. Be sure you enter the correct block size, start offset and disk order. If you seem to be having mixed results, it’s likely that one or more of the parameters are incorrect. Once a valid file system is recognized, you should be able to copy the data onto your backup media.
OTHER TIPS
RAID recovery due to the RAID meta data being lost (usually due to power outages or user error) are the easiest to recover from. RAID recovery due to a failed member disks is more difficult, but you may be able to rebuild it using the same steps if you can image and repair the failed disk. If you cannot remember the disk order, you can try piecing together a long text file (such as a log file with timestamps) using a hex editor. Also, if you can find the disk with the MBR (hardware RAID) or boot sector (software RAID), then you’ve found the first disk. One of the most common mistakes is entering the wrong block size when rebuilding a virtual RAID. Fortunately, you can go through some trial and error without causing further damage—as long as you are using disk images, and not the disks themselves.\ If you cannot recover or repair a failed member disk, then you may still be able to recover data from the other member disks. However, you will only be able to recover files that are smaller than the number of member disks minus one multiplied by the block size. While not entirely useful for video files and other large files, if you are looking for a single text file or email, you may have some luck.
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