Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Raid

714 views

Published on

  • Be the first to comment

Raid

  1. 1. RAID Redundant Arrays Of Independent Disks Group : 3 Miss Munni Unmul Habbiba (dc2013MCA00) Keyilamswabe (dc2013MCA00) Bikash dhal (dc2013MCA0028)
  2. 2. Introduction :
  3. 3. Solution: RAID  Technology that employs the simultaneous use of two or more hard disk drives to achieve greater levels of performance & reliability.  Several physical disks are set up to use RAID technology, they are said to be in a RAID array.  This array distributes data across several disks, but the array is seen by the computer user and operating system as one single disk.
  4. 4. Different Levels of RAID  RAID Level 0  RAID Level 1  RAID Level 2  RAID Level 3  RAID Level 4  RAID Level 5  RAID Level 6
  5. 5. Figure : RAID Level 0 (Striping)
  6. 6. RAID Level 0  Requires a minimum of 2 drives to implement.  The first byte of the file is sent to the first drive, then the second to second drive and so on.  Striping is the segmentation of logically sequential data, such as a single file, so that segments can be assigned to multiple physical devices
  7. 7. RAID Level 0  Advantages:  I/o performance is greatly improved by spreading the i/o load across many channels & drives.  Best performance is achieved when data is striped across multiple controllers with only one drive per controller.  Disadvantages:  It is not a “True” RAID because it is NOT fault-tolerant. The failure of just one drive will result in all data in an array being lost.
  8. 8. Figure : RAID Level 1 (Mirroring)
  9. 9. RAID Level 1 Data duplicated, also the controller card Requires only two drives to implement  Duplicate copies of data, so if a disk fails, data is still available and applications keep running. Advantages Better than single disk Simple to Implement Disadvantage - high check disk overhead.
  10. 10. Figure : RAID Level 2
  11. 11. RAID Level 2 Uses Bit-level striping with Hamming codes of ECC. Disks are synchronized and striped in very small stripes, often in single bytes/words. Hamming codes error correction is calculated across corresponding bits on disks, and is stored on multiple parity disks. Advantages Good read and write performance Disadvantages: High overhead for check disks Not used in modern systems
  12. 12. RAID Level 3
  13. 13. RAID Level 3 Uses dedicated parity disk. Requires a minimum of 3 drives to implement. Every write requires updation in parity data . Advantages improved performance and fault tolerance. Disadvantages:  One minor benefit is the dedicated parity disk allows the parity drive to fail and operation will continue without parity or performance penalty.
  14. 14. Figure : RAID Level 4
  15. 15. RAID Level 4 Uses Block-level striping with dedicated parity Requires minimum of 3 drives to implement Each disk operates independently which allows I/O requests to be performed in parallel. Advantages Read Performance is very good because of the blocks. Lowest overhead of check disks. Disadvantages Quite complex controller design Not commonly used
  16. 16. Figure : RAID Level 5
  17. 17. RAID Level 5 Uses Block-level striping with distributed parity Requires a minimum of 3 drives to implement Advantages Read performance very good. Lowest overhead of check disks. Disadvantages Most complex controller design. Difficult to rebuild in the event of a disk failure.
  18. 18. Figure : RAID Level 6
  19. 19. RAID Level 6  Raid Level 6 uses Block-level striping with dual distributed parity. Advantages: Continues to operate with up to two failed drives. Disadvantages Most complex controller design. Difficult to rebuild in the event of multiple disk failure.
  20. 20. THANK YOU

×