What is RAID? A High Level Overview (And Helpful Downloadable Guide)

By ·Categories: Tech Explained·Published On: July 31st, 2022·3.9 min read·

RAID stands for a Redundant Array of Independent Disks (or Redundant Array Inexpensive Disks). This data storage technology is used to combine multiple storage drives together into a single volume for a variety of purposes. RAID is used to improve performance, provide data protection through redundancy, or both. To answer “what is RAID”, let’s take a look at the different options for storage and different RAID types.

RAID vs. Backup

It is important to point out up front that RAID is not a substitute for backing up your data. RAID is all about redundancy so that no single point of failure will bring your operation down. So, while RAID facilitates business continuity, it falls short for disaster recovery. There are a lot of risks that RAID can’t protect against such as a natural disaster, voltage spike, malware, and of course, human error. All of which can result in data loss.

IT experts strongly recommend to keep a backup copy of your mission-critical data in at least two separate locations for disaster recovery.

What about JBOD?

JBOD is a storage controller setting that acts as a pass through for connected disks. When a RAID controller is in JBOD mode, the multiple disks are not configured in a RAID array, so there are no speed or fault tolerance benefits for storing data. Disks connected to a RAID controller set to JBOD mode act as if they are connected directly to the motherboard’s storage controller. JBOD literally stands for “Just a Bunch of Disks”, so it’s important not to confuse that setting with RAID.

Hot Swapping

Most RAID levels allow for hot swapping, meaning a drive in the array can be replaced without shutting down the host system. This is especially useful in programs and applications where critical data is stored. If that critical data becomes inaccessible for any amount of time, it could be a serious operational issue.

Shutting down an entire system for drive replacement can cause wide reaching downtime. For mission-critical programs and applications, significant downtime may have catastrophic and costly consequences. If hot swapping is critical for your application, make sure your RAID can support it.

Which Storage Solution Should You Choose?

Like many technology decisions, choosing your solution depends on what you need to do and how much you are willing to spend. You have many options for how to set up your disks and how to manage the data. Each option provides a slightly different balance of the key goals: reliability, availability, performance and capacity. 

For less critical needs, a simple implementation can be inexpensive and easy to implement. However, there are many instances where more expensive and complex hardware RAID solutions are preferable, particularly if you plan on storing and managing mission critical data. The diagrams below shows the variety of the most common RAID configurations from the simple to the complex.

Diagram of a RAID 0 configuration Diagram of RAID 1 Diagram of RAID 5 Diagram of RAID 6 Diagram of RAID 10 Diagram of RAID 50 Diagram of RAID 60

 

You will also have to select how to manage the distribution of data across all drives connected to it. The three methods to do this are with software, hardware, or firmware. Each method has its own benefits and drawbacks, and each offers a different level of reliability and performance. 

When it comes to cost, there are plenty of sayings that remind you not to be “penny wise and pound foolish” or “an ounce of prevention is worth a pound of cure”. There’s also the saying “you don’t need a sledgehammer to kill a fly.” We could go on, but you get our drift. Understanding the value of your data is your first step to understanding the best solution for your needs. 

Still not sure what is RAID? Download our helpful guide

Recent advancements in technology mean that you have many options. But, with the luxury of choice, comes the challenges of complexity. To help clear up some of this confusion, we’ve created The Ultimate Guide to RAID. This download takes a deep dive deep into the many different options for RAID setup and control. It also explores how each can help you balance costs and performance. Download the guide here!

Graphic to download RAID ultimate guide

Note: We originally published this blog on January 22, 2022. We updated the content on July 31, 2022. 

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About the Author: Sarah Lavoie

Sarah Lavoie is a content creator for OnLogic. When not writing, she can usually be found exploring the Vermont landscape with her camera looking to photograph something amazing.