What is RAID?

glossaryRAID is a way of providing extra performance, capacity and redundancy with hard drive storage.  It is an anachronym that stands for Redundant Array of Inexpensive Disks.  The examples in this article use 1TB hard drives.


RAID 0 is also known as striping.  It allows you to take 2 hard drives and add them together to increase storage.

  • If one drive dies the whole RAID is gone, which makes RAID 0 a risky RAID.
  • You gain capacity, 2 drives would add upto 2TB.
  • You also get improved read/write speeds.



RAID 1 is also know as mirroring.  It allows you to make one drive the exact copy of another drive.  When one drive dies the other seamlessly takes over.

  • You lose read/write performance.
  • You lose capacity (eg. 2 drives are only 1TB).
  • You gain redundancy in the event of disk failure.



You need at least 3 disks, and RAID 5 usually optimum with around 5 or 6 disks.  With RAID 5 you get the best of both worlds.

  • You lose a small amount of capacity (eg. 3 disks would add upto 2TB).
  • You gain read/write performance.
  • When any drive fails the remaining drives continue seamlessly.


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