|
Almost all SME, (Small to Medium Enterprises), have turned to RAID-configured storage on their servers in recent years for their mission-critical applications and data. In spite of being considered highly fault-tolerant, RAID does fail. RAID can fail due to component failure (including hard drives and controller cards), operating and application corruption, but most commonly, simple user error, often leaving the data unusable and corrupted.
RAID's are amongst the most complex media devices to recover data from. The data configurations are quite complex such as striped, volume, spanned etc. Sadly, different manufacturers will often use bespoke configuration applications that can add further complexity.
While state-of-the-art recovery tools and techniques are essential, ultimately it is the experience of both the recovery engineers and the software coders that makes the difference between a successful recovery and a failure. Successful RAID recovery often depends on an extremely fine-tuned sense of pattern recognition that is developed over years and years of recovering data from complex RAID configurations.
Disklabs Data Recovery and Computer Forensic Services is part of the 1 st Computer Traders Ltd group, which encompasses a company that repairs and sells hard disk drives, a company that specialises in surplus and end of line computer equipment, and of course a Data Recovery and Computer Forensics Services company.
|
|
|
Each
entire data block is written on a data disk; parity for blocks in the same
rank is generated on Writes, recorded in a distributed location and checked
on Reads.RAID Level 5 requires a minimum of 3 drives to implement
|
|
 Advantages
|
 Disadvantages
|
|
RAID
6 is essentially an extension of RAID level 5 which allows for additional
fault tolerance by using a second independent distributed parity scheme
(two-dimensional parity)
Data is striped on a block level across a set of drives, just like in RAID 5,
and a second set of parity is calculated and written across all the drives;
RAID 6 provides for an extremely high data fault tolerance and can sustain
multiple simultaneous drive failures
Perfect solution for mission critical applications
|
Very
complex controller design
Controller overhead to compute parity addresses is extremely high
Very poor write performance
Requires N+2 drives to implement because of two-dimensional parity scheme
|
Thanks to AC&NC for their technical input into this page.
|
