Thursday, November 5, 2009

Disk Redundancy using RAID

When studying for the CompTIA Security+ (SY0-201) exam, you'll come across using RAID for disk redundancy.

RAID is short for redundant array of independent (or inexpensive) disks. Redundancy provides fault tolerance. In other words, if a fault occurs in one drive, your system can tolerate the fault and continue to operate. Several different RAID types are available. When studying for Security+, you should be aware of the following topics.

  • RAID-0 (also known as striping) does not provide any fault tolerance but increased performance.
  • RAID-1 (also known as mirroring) uses two disks and provides fault tolerance.
  • RAID-5 (also known as striping with parity) uses at least three disks and provides fault tolerance while also providing increased performance. The equivalent of one drive is dedicated to parity.
  • RAID-10 (also called 1+0) combines RAID 1 and RAID-0. A variant is 0+1. Both provide fault tolerance and increased performance for specific applications.
Both hardware and software RAID solutions are avaialble. Hardware RAID is more expensive provides significantly better performance than sofware RAID.

Good luck in your studies