RAID Types

midterm topic

Disk Striping

• Is a method of storage that spreads data bits across all disks in the array, increasing performance and capacity

Disk Mirroring

• Actively duplicates bits across two disks to prevent data loss

RAID 0

• Uses disk striping to combine drives into one larger and faster logical drive

• Advantage:
  - Faster read and write because of disk stripping
  - Larger storage than any single disk
  - Only 2 disks are required, but more disks will increase capacity and performance

• Disadvantage
  - NO Data protection, if 1 disk fails - ALL data is lost

RAID 1

• Provides data protection by mirroring data across 2 disks

• Advantages:
  - Data protection: If 1 disk fails, there is no data loss
  - No performance loss if a disk fails
  - Fast recovery

• Disadvantages:
  - Max storage is limited to the size of a single disk
  - Does not increase performance or capacity

RAID 5

• Uses disk stripping to combine drives into one larger and faster logical drive and distributes parity across all disks in the array

• Parity Data is a smaller representative value that can be used to recreate data if data is lost

• Advantage:
  - If one disk fails, parity will be used to recreate the data
  - Larger storage than a single drive

• Disadvantage
  - THREE Disks are required: More disks will increase capacity not protection or performance
  - Parity is SLOW! Parity calculation may affect performance

RAID 6

• Similar to RAID 5 but adds another parity block

• Requires at least FOUR drives

• You could lose 2 drives and data would still be available

RAID 10 (1+0)

• Combines disk into RAID 1 arrays and then combines those arrays into a RAID 0

• Advantage:
  - Faster read/write because of disk striping
  - Larger storage
  - More disks = increased capacity, performance, and protection
  - Fast recovery: No performance lost if a disk fails

• Disadvantage:
  - FOUR disk minimum