Summary

In this chapter, you learned about fault tolerance and disaster recovery. Fault tolerance is the ability of a system to resist failures and faults and to recover from them by itself. Disaster recovery is the ability of a system to recover from some kind of disaster where data is lost. Disaster recovery methods are used to replace data that has been lost due to some unforeseen circumstance.

In the first section, you learned about the various ways to assess fault tolerance and disaster recovery needs and the various ways that network systems need fault tolerance and disaster recovery. You learned that the amount of money used to protect data should be proportionate to the value of the data and the ease with which it can be replaced.

In the next section, you learned about the various types of power management that are put in place to prevent problems from happening or to allow a system to recover from a small, power-related fault. These items include UPS, SPS, and surge protectors.

Following power management, you learned that the most critical component of a fault tolerance plan is the amount and type of disk fault tolerance implemented. Types of disk fault tolerance include RAID in its various forms. Additionally, you learned about the different methods of backup and how they apply to disaster recovery.

You also learned how important virus protection is to a network, and that if antivirus measures are in place, fault tolerance and disaster recovery are not needed. Viruses are small programs that can interrupt the normal function of a computer. Viruses can spread on a network like wildfire and must be eliminated before they have a chance to spread and cause damage.

Finally, you learned that, in order to keep systems running with the least amount of problems, a software patch must occasionally be applied. A software patch is a piece of software that temporarily fixes small problems within an existing program until the next major release of the software.