Adding Redundancy

Posted by Darril. in Security+ | 0 comments

Do you know how redundancy provides fault tolerance? You should if you plan to take the Security+ exam. Redundancy adds duplication to critical system components and networks. This post should help.

Redundancy into Systems and Networks

One of the constants with computers, subsystems, and networks is that they will fail. It’s one of the few things you can count on. It’s not a matter of if they will fail, but when. However, by adding redundancy into your systems and networks, you can increase the reliability of your systems even when they fail. By increasing reliability, you increase one of the core security goals: availability.

Redundancy

Redundancy adds duplication to critical system components and networks and provides fault tolerance. If a critical component has a fault, the duplication provided by the redundancy allows the service to continue as if a fault never occurred. In other words, a system with fault tolerance can suffer a fault, but it can tolerate it and continue to operate. Organizations often add redundancies to eliminate single points of failure.

You can add redundancies at multiple levels:

Disk redundancies using RAID
Server redundancies by adding failover clusters
Power redundancies by adding generators or a UPS
Site redundancies by adding hot, cold, or warm sites

Redundancy to Eliminate Single Point of Failure

A single point of failure is a component within a system that can cause the entire system to fail if the component fails. When designing redundancies, an organization will examine different components to determine if they are a single point of failure. If so, they take steps to provide a redundancy or fault-tolerance capability. The goal is to increase reliability and availability of the systems.

Some examples of single points of failure include:

If a server uses a single drive, the system will crash if the single drive fails. Redundant array of inexpensive disks (RAID) provides fault tolerance for hard drives and is a relatively inexpensive method of adding fault tolerance to a system.
If a server provides a critical service and its failure halts the service, it is a single point of failure. Failover clusters provide fault tolerance for critical servers.
If an organization only has one source of power for critical systems, the power is a single point of failure. However, elements such as uninterruptible power supplies (UPSs) and power generators provide fault tolerance for power outages.

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Although information technology (IT) personnel recognize the risks with single points of failure, they often overlook them until a disaster occurs. However, tools such as business continuity plans help an organization identify critical services and address single points of failure.

Remember this

A single point of failure is any component whose failure results in the failure of an entire system. Elements such as RAID, failover clustering, UPSs, and generators remove many single points of failure. RAID is an inexpensive method used to add fault tolerance and increase availability.

You might also like to view these posts:

Security+ Practice Test Questions

RAID and Security+ (RAID-0, 1, 5)

RAID and Security+ (RAID-6, 10)

Security+ Disaster Recovery

Security+ Practice Test Questions

SYO-501 Practice Test Questions Now Available

SYO-401 Practice Test Questions

Over 440 realistic Security+ practice test questions

All questions include explanations so you'll know why the correct answers are correct,

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Multiple quiz formats to let you use these questions based on the way you learn.

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SYO-401 Practice Test Questions

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Bonus - Performance Based Questions

Additional Security+ questions to help you prepare for the new performance based questions. These are included with the full bank of Security+ practice test questions and are divided into different sections. For example, you'll have access to the following links:

- Performance Based Question - Set 1

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of security to mobile devices and servers in a data center. You'll then have two questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 2

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of attacks with the name of the attack type. You'll then have five questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 3

You'll see a graphic showing a network with computers and servers separated by a firewall. The firewall is used to control traffic between the computers and users using rules within an access control list (ACL). You'll have three questions that test your knowledge and ability to correctly identify the relevant components of the rule. The incorrect answers and explanation provide you with insight into how to correctly answer this type of question on the actual exam.

- Performance Based Question - Set 4

You'll see a graphic explaining what you might be required to do on the actual exam related to what a forensic analyst would do during an investigation. You'll then have two questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 5

You'll see a graphic explaining what you might be required to do on the actual exam to match protocols and ports. You'll then have seven questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 6

You'll see a list of security controls along with a graphic showing devices and locations within an organization, along with instructions on what you might be required to do on the actual exam to match the controls with the devices and locations. You'll then have four questions that test your knowledge and ability to correctly answer the questions. This question also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 7

You'll see a list of authentication methods and authentication factors along with instructions on what you might be required to do on the actual exam to match the authentication methods with the authentication factors. You'll then have six questions that test your knowledge and ability to correctly answer the questions. This set also includes a link to a graphic showing the end solution for the overall performance based question simulation.

- Performance Based Question - Set 8

You'll see a graphic explaining what you might be required to do on the actual exam to match different types of attacks with the name of the attack type. You'll then have five questions that test your knowledge and ability to correctly answer the questions. This is similar to Set 2 but expands on the possibilities. The set also includes a link to a page showing the end solution for the overall performance based question simulation.

New - Performance Based Question - Set 9

New questions recently added using a different testing engine. See a demo here. This set includes drag and drop and matching questions on ports.

New - Performance Based Question - Set 10

A random set of 20 performance-based questions using drag and drop, matching, sorting, and fill in-the blank. This set includes performance-based questions on RAID.

Get the full bank of Security+ (SYO-401) Practice Test Questions Here

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See Chapter 9 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide for more information on redundancy.