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

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I’ve recently received a barrage of queries about RAID and Security+, so decided to write two posts to answer some of these questions to more people. This post covers RAID-0, RAID-1, and RAID-5. The next post covers RAID-6 and RAID-10.

First, RAID (redundant array of inexpensive disks) is mentioned in the Security+ objectives in the context of fault tolerance. Even if a disk fails, most RAID subsystems can tolerate the failure and the system will continue to operate. RAID systems are becoming much more affordable as the price of drives steadily falls and disk capacity steadily increases.

Some common types of RAID are summarized in the following table.

Type DisksFault ToleranceReadWrite
 RAID 0 Minimum 2 None High High
 RAID 1 2 only RAID-0 continues to operate even if one drive fails Medium Medium
 RAID 5 Minimum 3 RAID-5 continues to operate even if one drive fails High Medium
 RAID 6 Minimum 4 RAID-6 continues to operate even if two drives fail High Low
 RAID 10 Minimum 4 RAID-10 continues to operate even if two drives fail High High

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RAID-0

RAID-0 (striping) is somewhat of a misnomer because it doesn’t provide any redundancy or fault tolerance. It includes two or more physical disks. Files stored on a RAID-0 array are spread across each of the disks.

The following graphic shows the two disks with a file. Half the file is written on one disk and the other half is written on the other disk.RAID-0 and Security+

The benefit of a RAID-0 is increased read and write performance. Because a file is spread across multiple physical disks, the different parts of the file can be read from, or written to, each of the disks at the same time. This is useful for any systems that need fast input/output (I/O) performance, such as from a server that streams audio or video.

If you have two 500 GB drives used in a RAID-0, you have 1000 GB (1 TB) of storage space.

The following graphic illustrates what happens if a drive fails. You only have part of the file, which isn’t usable without the rest of the file. In other words, all the data is lost if one of the drives fail.
Failure RAID-0 and Security+

Remember this

RAID-0 (striping) provides fast input/output performance for reading and writing, but no fault tolerance. It requires a minimum of two disks. All disks are used for data storage.

Security+ Practice Test Questions

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Over 440 realistic Security+ practice test questions

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

and why the incorrect answers are incorrect.

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Multiple quiz formats to let you use these questions based on the way you learn.
  • Learn mode - randomized. View each of the questions in random order. Learn mode allows you to keep selecting answers until you select the correct answer. Once you select the correct answer, you'll see the explanation. Click here to see how learn mode works.
  • Learn mode - not randomized. View each of the questions in the same order. Use this if you want to make sure that you see all of the questions. Learn mode allows you to keep selecting answers until you select the correct answer. Once you select the correct answer, you'll see the explanation. Click here to see how learn mode works.
  • Test mode - randomized. View each of the questions in random order. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.
  • Test mode - not randomized. View each of the questions in the same order. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.
  • Test mode - 100 random questions. View 100 random questions from the full test bank similar to how the Security+ exam has a potential maximum of 100 multiple choice questions. In test mode, you can only see the correct answers and explanations after you complete the test. Click here to see how test mode works.

Get the full bank of Security+ Practice Test Questions Here

 SYO-401 Practice Test Questions Now Available


INCLUDES QUESTIONS TO HELP YOU PREPARE

FOR THE NEW PERFORMANCE BASED QUESTIONS 

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+ Practice Test Questions Here

Get the full bank of Security+ Practice Test Questions

RAID-1

RAID-1 (mirroring) uses two disks. Data written to one disk is also written to the other disk.

If you have two 500 GB drives used in a RAID-1, you have 500 GB of usable storage space. The other 500 GB of storage space is dedicated to the fault-tolerant, mirrored volume.

RAID-1 Mirror and Security+

You can add an additional disk controller to a RAID-1 configuration to remove the disk controller as a single point of failure. Adding a second disk controller to a mirror is called disk duplexing. It provides a separate disk controller for each disk.

RAID-1 provides a slight increase in read performance because systems can read data from both drives at the same time.

If one of the disks fails, the other disk still has all the data, so the system can continue to operate without any data loss. With this in mind, if you mirror all the drives in a system, you can actually lose half of the drives and continue to operate.

Failure RAID-1 and Security+

Remember this

RAID-1 (mirroring) provides fault tolerance and a slight increase in read performance, but no increase in write performance. It requires two disks. The equivalent of one drive is used for redundancy instead of extra storage space.

RAID-2, RAID 3, and RAID-4 are rarely used.

RAID-5

A RAID-5 is three or more disks that are striped together similar to RAID-0. However, the equivalent of one drive includes parity information that helps the drive provide fault tolerance.

If you have three 500 GB drives used in a RAID-5, you have 1000 GB of usable storage space. The other 500 GB of storage space is used for parity.

RAID-5 and Security+

The above graphic is a simplistic view of a RAID-5. The parity information is actually striped across each of the drives in a RAID-5 as shown in the following graphic.

RAID-5 and Security+ Drives

Because a system can read data from multiple drives at the same time, RAID-5 provides strong read performance. Add more drives and it becomes even faster. However, when writing to the drives, the system has to calculate the paritym which can slow down the write performance.

If one of the drives fail, the system can read the information on the remaining drives and recreate the actual data. In other words, a RAID-5 can tolerate the failure of a single drive. If two of the drives fail in a RAID-5, the data is lost.

Failure RAID-5 and Security+

Many disk vendors have been recommending the use of RAID-6 or RAID-10 instead of RAID-5 for any drives of 1 TB or larger. This is partly due to the unrecoverable error rate (URE) of standard SATA drives. If a URE occurs with a disk failure, it can prevent administrators from rebuilding a RAID-5 after a single disk failure. Also, due to the increasing size of hard drives, it takes a long time to rebuild a RAID-5.

Remember this

RAID-5 (striping with parity) provides fault tolerance and will continue to operate even if a single drive fails. It provides an increase in read performance, but no increase in write performance. It requires a minimum of three disks. The equivalent of one drive is used for parity instead of data storage space.

Continue to read about RAID-6 and RAID-10 here.

Practice test questions available on this site include many simulated performance-based questions, including a group of performance-based questions on RAID.

You might also like to view the post about Adding Redundancy.

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