RAID O
RAID 0 also known as a striped RAID consists of 2 or more drives. RAID 0 splits the data evenly across the available disks. RAID 0 is not a true RAID as it offers no redundancy and is primarily used for increased performance of the system. It is also often used to increase storage capacity for users with 2 smaller capacity drives to in turn create a much large volume.
Some common faults that we recover data from Raid 0 system are:
* One hard drive physically failing causing the array to fail.
* The File structure becoming corrupt on the array and losing the all the data.
* User error incorrect setup of the RAID. Confusing RAID 0 (Strip) and RAID 1(Mirror). So removing one drive thinking that all the data will still be on the other drive.
RAID 1
RAID 1 often referred as a Mirror RAID. The RAID works by writing the same information to two or more drives simultaneously. In effect, the data is written to a drive and the write process is simultaneously mirrored onto the second drive. This offers you a level of reliability not found with RAID 0. If one drive fails then a duplicate of all the data is on the other hard drive.
Some common faults that we recover data from this type of RAID are:
* Users not checking that the mirror is correctly setup and when the primary drive fails realizing that the data has not been written(mirrored) to the second drive.
* Unprotected power supply surging and blowing both hard drives.
* Following a catastrophic data loss the incorrect drive gets removed and the is then rebuilt over.
RAID 5
RAID 5 is the most common RAID configuration for Business and Corporate systems. The high level of redundancy provided, coupled with the possibility of high capacity makes this configuration more appealing than RAID 0 or RAID 0+1. The system works by spreading the parity (data) across the hard drives, if one drive was to fail then the array would continue without any loss of performance. If a second drive was to fail then the array would collapse.
Common Failures to Raid 5 arrays that we recover data from:
* Poor management of the array leaving 1 drive failed and not replacing the unit before a second drive fails.
* RAID controller losing the configuration/rebuild of array
* Incorrect removal of failed hard drive from the array then attempts to force the array to rebuild.