Tuesday, April 05, 2011

Security+ Exam Objectives 6.1

6.1 Explain redundancy planning and its components.
Disaster recovery plans are an important part of daily business to any type of organization. With proper disaster recovery plans the amount of downtime an organization experiences can be lessened if not avoided entirely. These plans ensure that daily activity can continue as necessary in the event of a disaster. It’s important for an organization to know how many failures can be tolerated, how to avoid them, and most importantly how to avoid single points of failure. Often time organizations use redundancy planning to come up with proper disaster recovery plans.

Hot site: In the event of an unplanned computer or equipment disaster a hot site can be relied upon to ensure that business can continue despite the disaster that has occurred. If a company’s data center were to become inaccessible or inoperable, a hot site will ensure that all of the information from the data center can be moved, viewed, and used in a hot site location. A hot site is completely equipped with not only hardware but office space, furniture, telephone jacks, and other necessities.

Cold site: A cold site, similar to a hot site in its purpose, is another kind of disaster recovery service that offers office space, but the customer must provide, install, and maintain all the necessary equipment. Generally cold sites are a lot less costly than hot sites but require more time and management, especially when it comes to recovering full operation.

Warm site: This is the best option as an alternative site in the event of the primary site going down. Warm sites have most of the equipment installed and ready to be operational, usually in less than a day. Before going back from the warm site to the primary site, the primary should be properly and professionally stress tested to determine whether or not the problem that put the site down in the first place has been resolved.

Backup generator: Gas operated generator in place in case of a power outage due to weather, a scheduled outage, or some other reason. They are required to keep networks and other pieces of hardware running.

Single point of failure: Single point of failures should be avoided in all costs. Usually through trial and error are these single points of failure realized. In an infrastructure a perfect example of a single point of failure is one part of an infrastructure that is critical to how the system runs, if this one part fails then the rest of the infrastructure will suffer as a result. In this case avoiding the single point of failure would be having a hot site or some other type of redundancy plan.

RAID: Redundant Array of Independent Disks. RAID is a technology, created in the 1980s, that provides an increased level of storage functions as well as reliability through the use of redundancy. When using RAID, this redundancy is achieved by combining multiple disk drive components into one unit. This unit is then used to distribute data across the drives in RAID levels. Nowadays RAID is mostly used when looking at computer data storage that can be divided and replicated on numerous disk drives.

Spare parts: Spare parts are a must have with any business or company that uses hardware equipment. Hardware is and will break, so having spare parts is necessary in order for everyday functioning to continue properly. It is best to have these parts in-house and readily available as opposed to having to order them and waiting for them to be delivered. Prompt access to these spare parts is important.

Redundant servers: Using redundant servers is a great way to reduce downtime. They can be used to reduce downtime as they are fitting in the case of hardware failure that causes an organization’s data center to become inoperable. With a downed data center a redundant server can be used to keep the site active and available. Redundant servers can even be used when a disaster completely renders an entire site to be unavailable.  Redundant servers also allow for little to no downtime in the case of schedule maintenance.

Redundant ISP: Just like redundant servers, a redundant ISP is a back-up service that can be consulted in the case of a problem with a company’s current ISP. Redundant ISPs are helpful when a company’s primary ISP link fails. With a redundant ISP there is a safety net and an alternate method to ensuring that communications can continue. Most organizations nowadays make use of having multiple-ISPs as to ensure that business continues in the event of a disaster, especially those that are weather related. With the growth of VOIP more and more companies have opted to use redundant ISP as a part of their disaster recovery plan.

UPS: Uninterruptible Power Supply, for a short amount of time a UPS can provide power when needed. They are generally used when an organization’s main input power source, fails, and needs to be temporarily replaced. Though plenty reliable, a UPS is not useful for long term issues. Generally a UPS is configured to be able to provide almost-instantaneous protection from input power interruptions.

Redundant connections: Redundant connections are needed to ensure that links between networks and sites remain active, even if one of the connections fails. This is usually done by leasing two lines from the same ISP or having multiple, readily available links up and running in the case of one of the links failing.

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