This introductory tutorial will teach you all you need to know about building your own RAID (Redundant Array of Inexpensive Disks), including why you would want to, the different types of RAIDs, and what sort of tools you can use to create them. So if you wish to learn how to configure two or more drives into a RAID, read on to learn more!

Why Would I Want to Configure a RAID

Before you do anything in life, you need to do one thing: Ask yourself why you would want or need to. This especially applies in the world of technology, where everything has a pro and a con.

If you came to this article from a search engine or clicked on it to read it from the front page, then no doubt you either have an idea of why you would want to create a RAID setup or want to find out why you should. With that in mind, I will attempt - in this section - to explain why you would want to create one.

One reason is for performance issues. A mirrored RAID (also known as Disk Mirroring) is a technique where one drive "mirrors" another, thereby increasing what is known as read performance (how fast a drive is "read" from by the CPU). This works because the drives are read in an alternating manner. Since both drives contain the same data, they are known as mirrors.

The second, perhaps more common, reason to do a RAID is for protection against data loss and data integrity due to disk failure. If you have sensitive data, operate a business, or have any important files you do not want to lose, then setting up a mirror RAID is not only a good idea - its practically mandatory.
Since the data you write gets "mirrored" onto another drive, it makes a copy and thereby "backs" the data up. Having two hard drives at the same time is not that common of an event, though it has been known to happen, so you will also want to make sure that you make frequent (read daily) backups of your data, in addition to running a RAID.

Standard Types of RAID

There are seven standard types of RAID, and a few non-standard RAID configurations. In this article we will only be covering the seven standard RAID configurations.

RAID 0

Commonly referred to as stripe set, RAID 0 evenly splits data across two or more hard drives. It is used specifically to improve the performance of a computer and is not used as a protective measure against drive failure. The reason for that is

the way the file system is distributed on a RAID 0 configuration - that is, part of it is contained on each drive. That means if one drive fails, it takes part of the file system with it, causing a system crash. What that means in layman terms is that for each drive in the RAID 0 configuration, the more likely you will encounter system failure.

Another thing to consider is that no matter how many drives you add, the total size of your RAID 0 will be dependent upon the smallest drive in your set. If you have a 500GB drive and a 1 TB drive, you will only have a 1TB setup, because the smallest drive is 500GB, meaning only 500GB of your 1TB drive will be available.

This setup is okay for gaming systems or application heavy systems that do not need to worry about data storage issues or that get backed up on a frequent basis. Also good for video and image editing setups.

RAID 1

RAID 1 creates a mirror copy of data across two or more hard drives. This data is copied across each drive, meaning that loss of data is less likely per drive you add to the RAID configuration. This holds true so long as - if one disk fails - you replace the failed drive immediately.

Note that this also only applies to physical drive failure, and not failure caused by a virus, as, due to the nature of a mirrored RAID, the virus would be copied across all drives, causing them all to fail.

RAID 1 also increases performance when it comes to reading, though writing remains the same as a single hard disk. One downfall to this type of setup is the cost to storage ratio, as you essentially lose the storage capacity of one drive per mirrored pair.

RAID 2

Do to the large number of drives required, this type of RAID configuration is not really used any longer and, for the sake of brevity, will be excluded in this article.

RAID 3

RAID 3 configurations require three hard drives. They work in a similar fashion to RAID 0, in that they are great for performance heavy systems. They differ from a RAID 0 however, in that they offer more system stability; they can survive the crash of one of the drives, so you do not have to worry as much about complete system failure.

Good for video editing, gaming, and so forth.

RAID 4

This configuration is very similar to RAID 3, except that it uses "blocks" instead of "bytes" for striping. While the read performance on this configuration is very high, the write is arguably the worst of all RAID configurations. Like RAID 3, it requires a minimum of three drives. Due to its poor writing and difficulty in the event of system failure, it is usually ignored in lieu of RAID 3 and RAID 5.

RAID 5

RAID 5 is also similar to RAID 3, but it has the highest Read rate of all standard configurations. The Write rate is fairly decent as well, and it is overall the optimal standard confguration. It can be tricky to rebuild in the event of a catastrophe, but is usually chosen for web-based and file servers.

RAID 6

RAID 6 is on level with RAID 5 with regards to performance, but it has an extra level of "fault tolerance", protecting a system in the event that two drives crash. It too is used for web-based and file servers, but comes with a pretty hefty overhead. A minimum of four hard drives are needed for this setup.

Summary

In this article we took a very brief glimpse into the different standard types of RAID systems. While the descriptions here are - to be fair - elementary at best, it serves as a basis for the remaining articles in this series, where we will set up and configure each RAID mentioned above.

DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware.

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