What is RAID ( Redundant Array of Inexpensive Disks)
On this article we have explained in details the concept of Redundant Array of Inexpensive Disks or RAID.
What is RAID or Redundant Array of Inexpensive Disks or RAID ?
RAID stands for Redundant Array of Inexpensive Disks or you can say Redundant Array of Independent Disks.
The basic idea behind RAID is to combine multiple small, inexpensive
disk drives into an array to accomplish performance or redundancy goals
not attainable with one large and expensive drive. This array of drives
appears to the computer as a single logical storage unit or drive.RAID
or Redundant Array of Inexpensive Disks allows information to access several disks.
RAID or Redundant Array of Inexpensive Disks uses techniques such as
1) Disk striping (RAID Level 0)
2) Disk mirroring (RAID Level 1)
3) Disk striping with parity (RAID Level 5)
4) Disk mirror and Disk striping ( RAID 10 )
1) Disk striping (RAID Level 0)
2) Disk mirroring (RAID Level 1)
3) Disk striping with parity (RAID Level 5)
4) Disk mirror and Disk striping ( RAID 10 )
To achieve redundancy, lower latency, increased bandwidth, and maximized ability to recover from hard disk crashes.
Here in all below Diagram B1, B2 , B3 , B4 , B5 , B6 are blocks and P1 , P2 , P3 represent Parity.
RAID 0 : This level of RAID is also known as ‘striping without parity..
Key points
| 1) This level of RAID makes it faster to read and write to the hard drives. 2) RAID 0 provides no data redundancy. 3) It requires at least two hard disks. 4) Reads and writes to the hard disks are done in parallel. 5) All hard drives in a RAID 0 array are filled equally. But since RAID 0 does not provide data redundancy, a failure of any one of the drives will result in total data loss. |
Key points:
| 1) This level of RAID mirrors information to two or more other
disks. In other words, the same set of information is written to two
different hard disks. If one disk is damaged or removed, you still have
all of the data on the other hard disk. 2) The disadvantage of RAID 1 is that data has to be written twice, which can reduce performance. 3) And it is expensive. 4) You need an additional hard disk for every hard disk worth of data. |
Key points:
| 1) This set of RAID or Redundant Array of Inexpensive Disks requires at least 3 Disks. 2) Distributes, or ‘stripes,’ parity information evenly across all the disks. If one disk fails, the data can be reconstructed from the parity data on the remaining disks. RAID does not stop; all data is still available even after a single disk failure. 3) RAID level 5 is the preferred choice in most cases: the performance is good, data integrity is ensured, and only one disk’s worth of space is lost to parity data. |
Key points
| 1) This set of RAID requires at least 4 Disks. 2)This level RAID provides high availability by combining features of RAID 0 and RAID 1.RAID 0 increases performance by striping volume data across multiple disk drives. RAID 1 provides disk mirroring which duplicates data between two disk drives. By combining the features of RAID 0 and RAID 1, RAID 10 provides a second optimization for fault tolerance. 3) RAID 10 stripes data across half of the disk drives .The other half of the array mirrors the first set of disk drives. 4) Access to data is preserved if one disk in each mirrored pair remains available so excellent redundancy and excellent performance. 5) It is expensive as you need more disks. * Source Article from : Internet |
