In computers, parity (from the Latin paritas: equal or equivalent) refers to a technique of checking whether data has been lost or written over when it's moved from one place in storage to another or when transmitted between computers.If you lose any one of the "N+1" pieces of data, you can recreate it from the "N" that remain, ... This property is exploited for parity calculation under RAID. ... This means a hardware controller that performs these calculations is required for high.
Asheesh jain
RAID or Redundant Array of Inexpensive Disks, is a method and technology of using multiple disks for increased size, performance, or redundancy. Imagine a tree, with each branch a different combination of mirroring, concatenation, striping, and parity. Combine this with hot spares, a high reliability can be achieved. The mirroring of drives makes them clones of each other, a physical redundancy in the case one dies. The concatenation of drives makes them appear as one large drive. This reduces redundancy as data is split between drives. The striping of data across drives, improves performance by dividing work. While one drive is writing, another drive can accept the next data to write. This reduces redundancy as data is split between drives. Parity is a calculated value, used to reconstruct data when a drive fails. Parity can be striped, or be assigned to a dedicated drive for parity only. Hot spares are automatically activated, and data is remirrored from the other or reconstructed from parity.
ARP = Air Raid Precautions.
john brown's raid
In fault tolerant disk arrays, such as RAID 5, a parity value is calculated for each bit of data at the same place on each disk in the array, and stored separately, so that the contents of any disk in the array can be calculated from the parity value and the contents of the other disks. This allows service to continue at reduced performance after the failure of any disk, and the failed disk can be replaced and the contents re-built without removing the array from service. Mirrored arrays, also known as RAID 1, simply maintain two copies, so that if one fails, the other can continue to serve. Simple disk striping doesn't attempt to store either a parity bit or a complete copy; it just spreads all data across all disks. This can significantly improve read performance, but if any drive fails, it is impossible to reconstruct the lost data, or continue service.
stephen decatur
RAID 7 is triple parity RAID 6 is double parity.
RAID DP ---Stands for RAID Dual Parity.....
Raid 5
RAID 5
RAID 3
RAID-5 provides data redundancy by using parity. Parity is a calculated value used to reconstruct data after a failure. While data is being written to a RAID-5 volume, parity is calculated by doing an exclusive OR (XOR) procedure on the data. The resulting parity is then written to the volume.
RAID level 3
parity
RAID 3
Raid 1 suppports the Mirroring if any one hard disk faild one will get the copy of the data and fault tolerent. after replacing the hard disk you have to re create the mirroring. Raid 5 supports stripped with parity the data will be deviced into blocks and stored in all the drives with the parity information. if any one or two hard disks faild the data will be available.
ghjkgh
There are three types of RAID RAID 0 (Stripping without parity) The records are distributed among all the available HDDs. The number of the HDDs may vary from one system to the other RAID 1 (Mirroring) This uses double number of HDDs. One stores the records while an equal number of HDDs forms the backup. RAID 5 (Stripping with parity) This type of raid distributes the records in n-1 disks while maintaining 1 disk as the parity disk. assuming 4 HDDs are required RAID 0 uses all the four RAID 1 uses double RAID 5 uses 4 + 1