When industries first started computerizing their records, data servers were like a collection of multiple storage drives, simply connected to a system with high processing speed. In those systems, if a single hard drive failed, the organization had to lose all the data, stored in that drive. Then, industries started keeping multiple copies of data in drives so that if one drive failed, there would be always a second drive as backup. But, this fashion of data storage increased the storage cost. Moreover, when one drive can fail, there is enough chance that the second backup drive may also fail at time. All these problems initiated the invention of a fault tolerant system, RAID server.
RAID stands for ‘Redundant Array of inexpensive Disks’. RAID is a technology to configure a single fault tolerant system by taking together multiple numbers of individual hard disk drives. The entire set of hard drives appears as a single logical drive and is managed through a controller, called RAID Controller. Apart from huge storage capacity, the main advantage of using RAID is its fault tolerant nature. RAID has such a storage architecture that if one disk fails and becomes completely inaccessible; still the data can be easily recovered from the other disks.
There are different types of RAID available, depending upon the number of hard drives as well as their fault tolerant mechanisms – RAID 0, RAID 1, RAID 5, RAID 50, RAID 6, RAID 6EE etc. In case of RAID 5 and above, if one hard disk fails, you can easily restore the data back. But, if there is a simultaneous failure of multiple hard drives, it can be problematic and a small mistake can make you lose all the data in the RAID array.
Apart from normal mechanical/electrical/firmware failure of hard drives, below are some of the prominent reasons behind RAID failure:
RAID controller failure
Damage to the RAID array configuration
Modification of the RAID configuration
RAID rebuild failure
Natural disasters (Fire, Earthquake, Flood etc.)
However, in any of the above situations of RAID failure, all the data from the inaccessible drives can be recovered by RAID recovery services. But, in this regard, the important thing is that RAID recovery is a strictly systematic process and needs experience, expertise and advanced infrastructure. Hence, for the safe recovery of the data from the troubled RAID drives, it is always advisable not to experiment with the system, post failure and immediately opt for the assistance of any good RAID data recovery service provider.