What is RAID 10: Nested RAID levels explained (2023)

RAID is a topic that comes up frequently when it comes to servers. If you've ever wondered what RAID is, why you would want it on your server, and if RAID 10 is the best option for you, look no further. We will discuss all of this in today's article.

What is RAID 10: Nested RAID levels explained (1)

In RAID 0, data is split across two disks (orange and red) for better performance but no redundancy.

What is RAID?

RAID or Redundant Array of Independent Disks is a technology for using multiple physical drives that behave like a single logical storage system. RAID is typically used to protect data in case one (or more) of these drives fails. Most RAID types also improve access speed and storage space compared to a single drive. A collection of drives in a RAID configuration is often referred to as a RAID array, or simply an array.

A RAID controller, which is software or hardware that manages the RAID array, is responsible for creating a logical volume (the array) from physical volumes (the drives). The logical volume appears to the operating system as a single drive, allowing any software to use multiple redundant drives without special programming.

(Video) 14.122 Nested RAID Levels 1+0; 10; 0+1; 01

Why would my server need RAID?

On the Internet, people expect the services they use to be available and fast at all times, and they expect their data to be secure. Lost data, downtime, or poor performance can damage your company's reputation and result in lost revenue.

An unfortunate fact is that between 1% and 10% of hard drives fail in any given year. With a RAID type that supports redundancy, your server can safely stay online with your data even if one hard drive fails. And while server CPUs have gotten hundreds of times faster over the past few decades, hard drive speeds are improving at a much slower rate.

Using multiple disks in a virtual array usually improves performance significantly. Because of these factors, RAID has become very popular for web servers and other internet-connected devices. RAID is a relatively inexpensive way to improve performance and reliability in this demanding environment.

Are there different types of RAID?

If you found this article on Google, you probably already know that there are multiple types of RAID: RAID 0, 1, 5, 6, 10, etc. What do they do? Each of these RAID types is known as a "RAID level," and the RAID level you choose will determine the system requirements, speed, reliability, and available storage space of the RAID array you are creating. Choosing the right RAID level is one of the most important decisions you can make when preparing your server for RAID.

What RAID level should my server use?

RAID on servers is a little different than RAID at home. For home use, the RAID levels you are likely to encounter are RAID 0 and RAID 1. RAID 0 and RAID 1 are inexpensive because they only require 2 drives and almost all hardware and software are compatible. This means that even home users can easily use them. However, RAID 0 offers no redundancy and is therefore unreliable. For RAID 1, it provides redundancy through mirroring, but only the same storage space as a single drive and no improvement in disk write speed. Because of these disadvantages, RAID 0 and 1 are best avoided in a business environment.

For servers, web hosting, and other business purposes, RAID 5, RAID 6, and RAID 10 are popular options. RAID 5 requires a minimum of 3 disks and RAID 6 and RAID 10 require a minimum of 4 disks. RAID 5, 6, and 10 are more expensive than RAID 0 or 1 because they require higher quality RAID hardware or software and also more hard drives. These RAID levels are popular because they offer a good combination of storage space, speed, and reliability.

(Video) RAID Levels Explained

RAID 10 is one of the most popular RAID options for web servers, VPS servers, and other internet-connected devices. For that reason, in the rest of this article, we'll focus on RAID 10 and how it compares to other common RAID types.

If RAID 10 is so popular, how does it work and why is it so good?

RAID 10 became popular because it offers the advantages of RAID 0 and RAID 1 and offers high performance, good reliability, and additional storage space compared to a single drive. RAID 10 is known as a "nested" RAID level because it literally "nestes" RAID 0 and RAID 1 together. Before we go any further, let's talk a little bit about nested RAID.

In RAID 10, the data is first divided into two RAID 1 arrays using RAID 0 (orange and red). Each RAID 1 array copies its data to two drives for redundancy.

What is nested RAID?

To understand RAID nesting, you need to understand the three types of RAID: mirrored RAID, striped RAID, and parity RAID. Each of these types is explained in detail in the articles linked above. Very briefly, here's how each works:

(Video) What is a RAID Array, RAID 0, 1, 5, 10. Advantages and Disadvantages of RAID 0. 1. 5 10

RAID mirroring means copying data from one drive to another for redundancy. RAID 1 is an example of mirroring.

RAID striping means having some data on one drive and some on another for extra space and speed. Raid 0 is an example of striping.

Parity RAID requires at least 3 drives and uses complex math so you can lose every drive and still keep all your data. RAID 5 is an example of parity RAID.

Nested RAID uses two of the above RAID types on a single array to take advantage of both RAID types. For example, RAID 10 uses striping and mirroring. This allows for the benefits of striping (additional speed, additional storage space) and the benefits of mirroring (data redundancy). Therefore, RAID 10 requires at least 4 drives. RAID 50 is another type of nested RAID that combines parity and striping. We will talk about RAID 10 in this article.

At a technical level, the order of the numbers used to identify a nested RAID level indicates how the levels are combined from bottom to top (i.e. the first number is the lowest level of the nested arrays). For example, as shown in the following diagram, RAID 10 provides a RAID 0 array of RAID 1 logical volumes.

This means you get the write speed improvements of RAID 0 with the redundancy improvements of RAID 1. In a RAID 10 configuration, you can lose a drive from any RAID 1 subarray without losing data. Because of this, the number of drives that can fail without data loss varies depending on which drives fail. The array is always operational in the event of a drive failure. With two drive failures, sometimes all data is lost and sometimes not. And if you lose more than half of the drives in a RAID 10 array, you always lose all of your data.

(Video) What Is Nested RAID

Nested RAID levels, while widely supported, are generally less supported than basic RAID levels. Cheaper "fakeraid" controllers, often included as a cheap feature on motherboards, often don't support nested attacks or parity. Also, some types of software intrusion do not support nested or parity intrusion.

Nested attacks require better quality attack hardware and more disks compared to simple RAID levels. The additional drives not only cost more on their own, but also require a computer that supports the additional drives, which take up more space and consume more power. All these factors make the nested attack more expensive and less common for home users. For this reason, nested RAID is more commonly found in servers and other enterprise and enterprise-class configurations.

Now that we understand nested RAID a little better, let's get back to why you might use RAID 10 on your server.

Why should I use RAID 10?

RAID 10 has several key advantages over other RAID levels:

  • RAID 10 has good data redundancy. A RAID 10 array always comes online when 1 drive fails, and sometimes stays online even if up to half of its drives fail (when the "right" drives fail). RAID 0 always fails if one drive fails, and RAID 5 always fails if 2 or more drives fail.
  • Because it supports striping, RAID 10 offers more storage space than RAID 1.
  • RAID 10 is fast. A 4-drive RAID 10 provides twice the read and write speeds of a 2-drive RAID 1, twice the read speed of a 2-drive RAID 0, and a much faster write speed compared to a 4-drive RAID 6 or RAID 6.
  • RAID 10 is well supported by most software and hardware. This could be an issue with Raid 5, 6, 50 and 60.
  • Unlike Raid 5, 6, 50 and 60, Raid 10 works well even if you don't have an expensive hardware-accelerated raid controller.

Why doesn't everyone use RAID 10?

While RAID 10 has many advantages, it's not perfect for all situations. Here are some disadvantages of RAID 10:

  • RAID 10 requires at least 4 drives. RAID 0 and 1 require only 2 drives and RAID 5 has a minimum of 3 drives. This can increase costs.
  • RAID 10 may not be supported by cheap "fakeraid" controllers that only work correctly with raid 0 or 1.
  • With RAID 10, you lose half of the storage space to mirroring. RAID 5, 6, 50, and 60 can provide more available disk space with the same number of drives. This is important for applications like backup where storage space is more important than speed.
  • Outages can be unpredictable. While you can lose 1 drive at a time, losing 2 drives at once can result in data loss. If you always need to lose 2 drives without losing data, RAID 6 can do it and RAID 10 cannot.

Learn more about RAID

I hope this overview gives you an idea of ​​what RAID is for, how nested RAID works, and if RAID 10 is right for you. If you want to learn more about RAID, stay tuned for one of the following articles:

(Video) What is RAID? RAID 0, RAID 1, RAID 4, RAID 5, RAID 6, Nested RAID 10 Explained

  • Erklärung der RAID-Level: RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50 oder RAID 60.
  • How to install and configure RAID
  • Which is better: software RAID or hardware RAID
  • How to choose a hardware RAID card
  • RAID and Backups: What's the Difference?

When you're ready to get started with a server with RAID, one of the easiest ways to do that is with a dedicated serverIOFLOOD.com.contact usToday we're happy to explain your options and help you choose the configuration that's right for you.


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