RAID is short for Redundant Array of Independent (or Inexpensive) Disks, a category of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers and increasingly being employed on personal computers. Array is the operative word, which also dictates what the cure is going to be, when a RAID disk recovery situation arises.
RAID disk repair, as you may expect is quite a complicated process. But the good thing going for it is the chances for retrieving lost data is higher than with most other types of disks because the typical RAID architecture strategically distributes data randomly across the array. What this sort of architecture demands of recovery professionals is to specialize in the disk???s many different levels.
In a nutshell, these are all the levels that the RAID disk recovery team is up against. RAID 0, 1, 0+1; RAID 3, 4; RAID 5; RAID 10; Hardware RAID including: AMI, Compaq, Dell, Adaptec, IBM, etc.; and, Software RAID including Mac OS; Windows Servers including 2K, XP, NT; Linux, Solaris, Novell, etc.
Just some RAID systems that most RAID disk recovery specialists should all be familiar with are: Quantum Snap Server; Maxtor MaxAttach; Adaptec AAA131; Compaq; Dell Perc Systems; IBM; AMI; Mylex; and yes, many others!
The two most common implementations of the RAID architecture are Levels 4 and 5. Level 4 provides block stripping with a parity check. When a data disk fails, the parity data is used to create a replacement disk. Level 5 provides data stripping at the byte level and also stripe error correction information, which results in excellent performance and good fault tolerance. These two types are certainly the best friends of the RAID disk recovery expert as these are the easiest to restore when the situation arises.
Brad Triggs provides more information on Data Recovery at his website:
Data-Recovery-Central.com - RAID Data Recovery