Raid 0 :
It is the Stripped Disk Array with no fault tolerance and it requires at least 2 drives to be implemented. Due to no redundancy feature, RAID 0 is considered to be the lowest ranked RAID level. Striped data mapping technique is implemented for high performance at low cost. The I/O performance is also improved as it is loaded across many channels. Regeneration, Rebuilding and functional redundancy are some salient features of RAID 0.
Raid 1:
It is the Mirroring (Shadowing) Array meant to provide high performance. RAID 1 controller is able to perform 2 separate parallel reads or writes per mirrored pair. It also requires at least 2 drives to implement a non-redundant disk array. High level of availability, access and reliability can be achieved by entry-level RAID 1 array. With full redundancy feature available, need of readability is almost negligible. Controller configurations and storage subsystem design is the easiest and simplest amongst all RAID levels.
Raid 2:
It is the combination of Inherently Parallel Mapping and Protection RAID array. It's also known as ECC RAID because each data word bit is written to data disk which is verified for correct data or correct disk error when the RAID disk is read. Due to special disk features required, RAID 2 is not very popular among the corporate data storage masses, despite the extremely high data transference rates.
Raid 3 :
RAID 3 works on the Parallel Transfer with Paritytechnique. The least number of disks required to implement the RAID array is 3 disks. In the RAID 3, data blocks are striped and written on data drives and then the stripe parity is generated, saved and afterwards used to verify the disk reads. Read and write data transfer rate is very high in RAID 3 array and disk failure causes insignificant effects on the overall performance of the RAID.
Raid 4 :
RAID 4 requires a minimum of 3 drives to be implemented. It is composed of independent disks with shared parity to protect the data. Data transaction rate for Read is exceptionally high and highly aggregated. Similarly, the low ratio of parity disks to data disks indicates high efficiency.
Raid 5 :
RAIDS 5 is Independent Distributed parity block of data disks with a minimum requirement of at least 3 drives to be implemented and N-1 array capacity. It helps in reducing the write inherence found in RAID 4. RAID 5 array offers highest data transaction Read rate, medium data transaction Write rate and good cumulative transfer rate.
Raid 6 :
RAIDS 6 is Independent Data Disk array with Independent Distributed parity. It is known to be an extension of RAID level 5 with extra fault tolerance and distributed parity scheme added. RAID 6 is the best available RAID array for mission critical applications and data storage needs, though the controller design is very complex and overheads are extremely high.
Raid 7 :
RAID 7 is the Optimized Asynchrony array for high I/O and data transfer rates and is considered to be the most manageable RAID controller available. The overall write performance is also known to be 50% to 90% better and improved than the single spindle array levels with no extra data transference required for parity handling. RAID 7 is registered as a standard trademark of Storage Computer Corporation.
Raid 10 :
RAID 10 is classified as the futuristic RAID controller with extremely high Reliability and performance embedded in a single RAID controller. The minimum requirement to form a RAID level 10 controller is 4 data disks. The implementation of RAID 10 is based on a striped array of RAID 1 array segments, with almost the same fault tolerance level as RAID 1. RAID 10 controllers and arrays are suitable for uncompromising availability and extremely high throughput required systems and environment
