Thursday, November 19, 2009


When preparing for the CompTIA Security+ (SY0-201) exam, you should understand some basics about redundancy from redundant disks all the way to redundant sites.

Some key points to remember are:

  • RAID-0 does not provide any fault tolerance.
  • RAID-1 is also known as a mirror and includes two disks.
  • RAID-5 is also known as striping with parity and includes three or more disks with the equivalent of one drive dedicated to parity.
  • Hardware RAID solutions are more efficient than software RAID but generally cost more to implement.
  • Failover clusters can be used to provide redundancy for servers.
  • Redundant WAN links (such as T1 or partial T1 lines) can be used to provide redundant connections. A second ISP can be contracted to provide redundant connections to the Internet.
  • A hot site includes the equipment, software, and communications capabilities of the primary site with all the data up-to-date.
  • A hot site can take over for a failed primary site within minutes. It is the most effective disaster recovery solution for an alternate site, but it is also the most expensive to maintain.
  • A cold site includes only the very basic utilities and is the hardest to test.
  • A warm site is a compromise between a hot site and a cold site.
Good luck in your studies,

Darril Gibson

CompTIA Security+: Get Certified Get Ahead: SY0-201 Study Guide