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RAID Data Recovery Software - Acronis
Article Written by Jeff Grundy

RAID Data Recovery Software

This article covers:

  • What RAID is and how it works
  • Various RAID types and their differences
  • RAID redundancy and data recovery options
  • Methods for creating RAID backups
  • Backing up RAID with Acronis True Image

RAID - The Basics

RAID is an acronym that stands for "redundant array of independent disks." In this article, we will cover what RAID is, how it works and the various RAID data recovery options that are available.

RAID is used to combine two or more individual disk drives into a single logical drive to increase storage space and/or performance. Back in the days when hard drives were far less spacious and much more expensive, manufacturers introduced RAID as a way of combining multiple, less-expensive hard drives into an array that provided higher capacity and better performance with a single volume.

Storage and Performance Benefits

In addition to space and performance benefits, RAID was also designed to improve redundancy (sometimes referred to as fault tolerance or failover protection), which ensures that data remains accessible and available if a part of the array fails.

RAID Today - Still Beneficial and Useful

While modern hard drives are considerably cheaper and offer much more space than when the array technology was first introduced), RAID is still an excellent way of augmenting storage and improving disk drive performance. The intent of this article is to provide you a better understanding of RAID. So we will discuss how RAID works, its benefits, potential data security issues with RAID and how to safeguard data stored in such an array.

How RAID Works

When RAID was introduced in 1987, the average size of a large-capacity hard drive was only about 40 MB. So computer scientists at the University of California at Berkley came up with the idea of stringing together a number of smaller-sized disk drives to create one large drive, which would otherwise be expensive and difficult to produce.

For example, take an 800 MB hard drive, which was virtually non-existent in 1987 (save for some custom produced drives used in supercomputers and specialty labs). The inventors of RAID showed that they could take ten 80 MB drives and a special hard drive controller and make the entire setup appear as one single volume (or drive) to the operating system. The result was a usable single drive volume that offered more capacity and better performance.

Modern RAID works essentially the same way. However, these days some operating systems support software RAID options in addition to hardware-based controllers. While there are several significant differences between hardware and software implementations, the end result is similar - multiple drives used to create large singular volumes.

RAID is Separate from the Rest of the Computer

Whether implemented via hardware or software, RAID functions independently from the rest of the computer and requires its own control panel or configuration utility. Regardless of the number of drives used in the RAID, the computer (to which the array attaches) sees the entire setup as a single ordinary disk drive. What the computer is actually seeing is the RAID controller (or software driver) that masquerades as a single volume, not the physical drives themselves. The RAID controller or driver performs all of the actual coordination and management of the individual drives in the array.

RAID Types (Levels)

As mentioned above, there are two primary implementation methods for RAID: hardware controller-based arrays and those created and configured with a software driver. There are also some occasions when data is distributed across a RAID using a combination of hardware and software.

While there are only two primary RAID implementation methods, there are several types of arrays used in various situations. The various types of RAID are known as "levels," and those levels determine how an array is configured and how data is split or distributed across the volume. The RAID level also determines the type of data recovery available for the array (if applicable) by way of parity or redundancy (more on redundancy a little later.) Common levels of RAID include:


With RAID 0, data is split across two or more disks for the sole purpose of improving throughput performance. Individual files are written to and read from multiple disks, which offers the advantage of using the speed of all the disks. Often referred to as "striping," RAID 0 does not offer any type of redundancy or fault tolerance. Therefore, if one drive in fails, data recovery is not possible as the entire array breaks and all data is lost.



Also known as "disk mirroring," RAID 1 writes data to a pair or pairs of disk drives simultaneously. Whereas RAID 0 is designed primarily for speed, RAID 1 is meant to provide redundancy. If one disk in the array fails, the computer is still able to access data from the remaining drive(s) in the RAID. After replacing a faulty drive in a RAID 1 setup, the controller or driver copies data from the remaining, functioning drive to the new one automatically, thus restoring the array and its redundancy. RAID 1 is the simplest method of failover storage and enables basic data recovery with the replacement of the faulty driver. RAID 1 offers relatively fast read speeds but write speeds are slower than with RAID 0. A potential disadvantage of RAID 1 is that you must double the number of drives used to obtain the desired storage capacity. The minimum number of drives for RAID 1 is two.



RAID 5 (Striping with Parity)

Like RAID 0, RAID 5 stripes data across multiple hard drives. Unlike RAID 0, though, RAID 5 also stores parity information on the drives. In a nutshell, parity is a small amount of data that is used to accurately describe and reference larger data sets. In the event one of the drives in the array fails, parity data stored on the other drives in the RAID can be used to recreate the data on a new drive and thus restore the array. It should be noted that parity data can consume up to about one-third of a drive's usable space.

RAID 5 offers the benefits of fault tolerance and relatively fast performance. But when used in environments where large numbers of write operations are required, performance may suffer due to the overhead caused by writing parity data to the drives. Using the control panel firmware or software included with the controller card, RAID 5 data recovery is generally possible as long as no more than one drive in the array fails at any given time. If two drives in the array fail at the same time, data recovery is not possible. The minimum number of drives for RAID 5 is three.


RAID 6 (Striping with Parity)

RAID 6 is similar to RAID 5, but offers more reliability as it stores an extra block of parity data. The second parity block means that it is possible to perform RAID 6 data recovery and rebuild the array even if two drives attached to it fail at the same time. Nevertheless, if a power surge or other physical disaster destroys more than two drives in the array, a RAID recovery or rebuild is not possible. The minimum number of disks required for RAID 6 is four.


RAID 10 (Striping and Mirroring)

RAID 10 (or Raid 1 + 0 as some refer to it) combines the features of both RAID 0 (striping) and RAID 1 (mirroring). Therefore, it provides the redundancy and data recovery ability of RAID 1 with the higher performance of RAID 0. RAID 10 is often used in environments that require higher levels of data security, reliability, and high performance. The minimum number of drives for a RAID 10 implementation is four.



JBOD, or "just a bunch of disks," is not really a RAID level in the truest sense as there are no striping or performance benefits. Nevertheless, since JBOD is often configured using a RAID controller (or RAID-like features in the operating system), it's often mentioned when discussing RAID. To put it simply, though, JBOD is just a series of standard hard drives strung together.

With JBOD, each drive can function as its own volume and have its own drive letter, or all the drives can be connected or "spanned" to form a single logical volume (with a single drive letter.) If you assign multiple volumes and drive letters to the disks in a JBOD array and one of the drives later fails, only data on that particular drive is lost. If you span the drives to create a single volume and a drive fails, then all data on other drives connected to the volume is lost as well. The minimum number of drives for JBOD is two.


Other RAID Types

The above-mentioned RAID levels are the ones most commonly used by consumers and enthusiasts. However, there are many other RAID levels implemented in various enterprise and server environments. Nevertheless, most other RAID levels are merely combinations of other types (such as RAID 50 and RAID 100). Other less common RAID types include RAID 2, RAID 3, RAID 4 and MAID (massive array of idle disks). Just like the ones mentioned above, these levels and types offer varying levels of redundancy and RAID array data recovery possibilities. And as with more commonly used RAID levels, proprietary and non-standard types suffer from the same limitations (if drives in the array fail, then data on other disks might be lost as well.)

About RAID Redundancy

As it relates to RAID and storage, redundancy means the use of more drives or disks than necessary to store data. Or to put in simpler terms, store the same data in multiple locations or on multiple disks.

Redundancy is one of the biggest strengths of RAID and something that is essential to any good backup strategy. And while many RAID levels provide a degree of redundancy, there is one potential pitfall - the redundant data is stored in the same array. This means that if too many drives in the array fail all at once, or if there is a physical disaster (fire, flood, etc.), then all of the data is just gone. That is unless you have a backup in another location.

Additional Redundancy Required

If you want to ensure that your RAID data is always accessible and secure, you will need to create a backup that is stored on other media or off-site. Creating additional backups of your RAID data and storing it on other media or in the cloud will save you a ton of frustration, time and money if the drives in your RAID fail or are damaged.

Why a RAID is not an Ideal Backup Solution

One of the biggest misconceptions regarding RAID is that it is always a reliable backup option. While RAID can be used to back up other drives (or even other arrays,) it is not a true backup if it is used as the primary storage destination for the computer or network to which it attaches. So if you use RAID to back up computer data from a separate drive, then the array can be considered a backup. If you use the RAID as your primary storage source, it cannot.

The reason you should never consider RAID used for primary storage as a backup is simple: if you delete or lose files stored in the RAID, they are gone forever. When using RAID as primary storage, any changes or deletions made to files are treated just as they would be with a standard hard drive - no backups or previous versions are kept. That is unless you use a true backup application that allows you to recover deleted files from a copy stored on other media or in another location.

RAID Can Play a Part

It's also important to note that even if you do use RAID to backup files from another hard drive, the array should only be considered just a small part of your overall backup strategy. Therefore, you should follow the 3-2-1 rule to make sure your data is always protected. The 3-2-1 rule states that you should:

  • Create three copies of your data
  • Store the data in at least two different formats (such as RAID and cloud)
  • Make sure at least one of the copies is stored off-site


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Acronis True Image - The Complete RAID Backup/Recovery Solution

There are a few different ways you can back up data from your RAID to ensure you have access to it if the array fails or is lost. For instance, you could copy files from the RAID to another RAID or external hard drive or you could upload some of your files to a cloud storage provider, like Google Drive or Dropbox.

But the time and effort needed to back up RAID data to other local storage and cloud accounts can be considerable if you must perform each action manually. With a first-rate backup application like Acronis True Image, you can create accurate, reliable and secure backups quickly and easily.

Local and Cloud Backups - Quick and Easy

Acronis True Image provides multiple backup options that enable you to store your backups both locally (on other hard drives or another RAID) or in the secure Acronis Cloud. With Acronis True Image, you can create full, partial or incremental backups of your RAID with just a couple of mouse clicks.

quickeasy acronis 

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Universal Restore

Acronis True Image is recognized by millions as the best hard drive recovery software available. Part of the reason for that is our Universal Restore feature. With Universal Restore, not only can you recover or restore your RAID data to a new array if needed, but you can also transfer backup data to another system, other storage devices, or even to your smartphone.

So, whether you need to ensure reliable RAID 5 data recovery or need an easy and effective RAID 0 data recovery solution, check out Acronis True Image and discover why it is the RAID backup solution of choice for consumers and businesses everywhere.


Published Monday, July 24, 2017 8:09 AM by David Marshall
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