RAID systems support different types of configurations such as 0, 1,
4, 5 and linear. They have the following characteristics:
Level 0 – This level is also known as “striping” because the
information saved in the hard drive is split evenly across two or more disks. The storage capacity
is the same as of one hard drive, and the failure of one hard drive will
result in data loss.
Level 1 - This level is best known as “mirroring”. In this case, the system
duplicates and stores the information in more that one disk. Therefore,
it is still possible to recover the files in the event that one disc
failed completely. RAID 1 writes identical information in each disk of
the unit; thus, keeping several copies that can help retrieve the data.
Level 4 – This system confines all parity data to a single disk. The storage capacity on this level
equals the total capacity of all drives minus the capacity of one.
Level 5 – This is the most popular and widely used system
because it distributes the tables among all the drives in the unit. It
also solves the bottleneck issue . The
only botleneck would be the process in which the tables
are calculated. The storage capacity on this level equals the
total capacity of all drives minus one.
Linear RAID – This system is composed of a group of hard drives of
equal or different capacities to create a virtually bigger unit. The
information is stored in sequential order on the next drive once the prior has been filled. Unfortunately, the reliability
factor of this system is rather sparse. If one of the hard drives fails,
the other drives can not be used as a back up to retrieve the
information. The capacity equals the total capacity of all the hard
drives as a group.