RAID LEVELS
RAID
LEVEL 0
- Minimum 2 disks.
- Excellent performance ( as blocks are striped ).
- No redundancy ( no mirror, no parity ).
- Don’t use this for any critical system.
RAID LEVEL 1
- Minimum 2 disks.
- Good performance ( no striping. no parity ).
- Excellent redundancy ( as blocks are mirrored ).
RAID LEVEL 2
- Each bit of data word is written to a data disk drive.
- An error-correcting code is calculated across corresponding bits on each data disk
- On read, the code verifies correct data or corrects single disk errors.
RAID LEVEL 3
- Requires only a single redundant disk.
- Employs parallel access, with data distributed in small strips.
- A simple parity bit is computed for the set of individual bits.
- Can achieve very high data transfer rates
RAID LEVEL 4
- Uses multiple data disks, and a dedicated disk to store parity.
- Each entire block is written onto a data disk
- RAID 4 requires at least three disks for complete implementation and configuration.
RAID LEVEL 5
- Organized in a similar fashion to RAID 4.
- Difference is distribution of the parity strips across all disks.
RAID LEVEL 6
- Two different parity calculations are carried out and stored in separate blocks on different disks.
- Advantage is that it provides extremely high data availability.
HI FRIENDS I AM DHANESH. I ADD THIS BLOG FOR AN EDUCATION PURPOSE