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