Rapid Recovery
Redundant Array of Independent Disks, or RAID, is an advanced technology introduced to the storage field as a way of increasing reliability and performance. RAID is most commonly seen in high performance machines, or in business environments where redundancy is crucial. RAID setups are available in several forms, each emphasizing a different function.
RAID 0 arrays provide the maximum reading and writing performance possible, with the size of the array directly affecting performance. A RAID 1 array provides the greatest reliability without much of a difference in performance. RAID 5 is the most common setup, combining reliability with increased performance.
The RAID 0 setup is the most vulnerable to failure. RAID 0 offers improved performance because each drive is given only a segment of the file to handle, allowing the disks to operate simultaneously. The danger is that the failure of one drive may result in unrecoverable data corruption. As the RAID 0 array grows larger, the risk of this failure increases. No matter the size of a RAID 0 array, it only takes one hard drive failure to cause the entire stack to malfunction. RAID 5 arrays use mirror and striping storage techniques to ensure that the failure of one drive does not affect the others.
In heavy duty production environments, where uptime is critical, some RAID systems may support “hot swapping.” In a hot swappable system, the hard drives can be changed out without ever disrupting the functionality of the system. With a RAID 1 array, this concept of mirror storage is taken to an extreme. All hard drives in a RAID 1 array contain the same data, meaning that every hard drive except one may fail, and the system will continue to function.
In the most common RAID 5 setup, it is very important to immediately repair or replace a damaged hard drive. After the first drive fails, it becomes possible for any further failures to destroy data. Fortunately, RAID recovery is not very complicated if the failure is due to a software issue such as a missing partition. A number of freeware utilities on the internet can restore RAID devices to working order. Just be sure when downloading a utility that the program supports RAID recovery, and supports the right type of RAID setup. RAID is slightly more difficult for a utility to handle, but there are many written for just such purposes.
In a situation where hardware failure is involved, it is just as difficult to accomplish RAID recovery as it is with a single hard drive.
Mechanical failures involving the reading and writing heads are practically impossible to recover from, and will require the services of a professional such as DriveSavers. A hardware failure involving the logic circuit mounted to the hard drive are somewhat easier to recover from, and may result in a working hard drive again. Repairing this problem is a matter of tracking down an identical drive (same firmware) and replacing the broken logic board with a new one.
Filed under: Rapid Recovery