A hardware RAID implementation requires at minimum a RAID controller. On a desktop system this may be a PCI expansion card, PCI Express expansion card or built into the motherboard. Controllers supporting most types of drives may be used – IDE/ATA, SATA, SCSI, SSA, Fibre Channel, sometimes even a combination. The controller and disks may be in a stand-alone disk enclosure, rather than inside a computer. The enclosure may be directly attached to a computer, or connected via SAN. The controller hardware handles drive management and performs any parity calculations required by the chosen RAID level.
Hardware RAID Failures:
- Actuator Failure
- Bad sectors
- Controller Failure
- Controller Malfunction
- Corrupted RAID
- Lightning, Flood and Fire Damage
- Damaged Motor
- Drive physical abuse
- Hard disk component failure and crashes
- Hard disk drive component failure
- Hard drive crashes
- Hard drive failure
- Head Crash
- Intermittent drive failure
- Media Damage
- Media surface contamination
- Multiple drive failure
- Power Spike
- Power Supply Burn out or failure
- RAID controller failure
- RAID corruption
- RAID disk failure
- RAID disk overheat
- RAID drive incompatibility
- RAID drive overheat
- RAID Array failed
- Vibration damage
Hardware RAID Failures(Human Error):
- Unintended deletion of files
- Reformatting of drives / Array
- Reformatting of partitions
- Incorrect replacement of media components
- Accidentally deleted records
- Mistaken overwritten database files
- Employee sabotage
- Lost/Forgotten password
- Overwritten files
- Overwritten RAID config files
- Overwritten RAID settings
- RAID incorrect setup
- RAID user error
Software RAID implementations are now provided by many operating systems. Software RAID can be implemented as:
- layer that abstracts multiple devices, thereby providing a single virtual device (e.g. Linux’s md).
- a more generic logical volume manager (provided with most server-class operating systems, e.g. Veritas or LVM).
- component of the file system (e.g. ZFS or Btrfs).
Software RAID Failures:
- Back up failures
- Computer virus and worm damage
- Corrupt files / data
- Damaged files or folders
- Directory corruption
- Firmware corruption
- Repartition
- Server registry configuration
- Missing partitions
- RAID configuration
- Reformatting
Software RAID Failures(Application Failure)
- Applications that are unable to run or load files
- Corrupted files
- Corrupted database files
- Data corrupted
- Locked databases preventing access
- Deleted tables
About RAID Data Recovery
The majority of Small-to-Medium Enterprises across the globe have turned to RAID-configured systems for their storage solutions. The most frequently cited reasons for utilizing RAID Arrays in businesses today are the highly fault-tolerant level the solution offers and the cost effectiveness of acquisition and maintenance.
However, if a RAID Array does fail due to component malfunctions (including hard drives and controller cards) or operating and application corruption, it leaves the data unusable and in most cases corrupted.
RAID data recovery is an intricate task since RAID data configurations are often custom-built applications developed by competing manufacturers. Without in-depth knowledge of how RAID arrays are configured at both a hardware, firmware and software level, data recovery attempts will not only fail, but result in further data corruption.