What Is Disk Redundancy?

by Dan Stone

Disk redundancy is a term used to describe creating a one-to-one copy of a hard drive on a secondary or backup hard drive that can be used to replace the original hard drive in the event that it fails. Disk redundancy is often achieved by configuring a Redundant Array of Independent Disks setup within a computer to automatically construct a backup copy of all the information on a hard drive. Disk redundancy can also be achieved by making a backup clone hard drive within Windows.

How to Create a Redundant System Image


Connect the second hard drive to the computer.


Open the charms bar and select the "Search" option.


Search for "File History" and select the "File History" feature from the results list.


Select the "Windows 7 File Recovery" link from the bottom of the "File History" window.


Choose the "Create a System Image" option.


Select the "on a hard disk" radial and choose the second hard drive from the list.


Click the "Let Windows choose" option and press the "Next" button to make a system image on the second hard drive.

How to Configure a RAID Mirrored Hard Drive


Internally install the second hard drive inside the computer.


Load Windows, open the charms bar and select "Search."


Search for "Computer Management" and select "Computer Management" from the list.


Select "Disk Management" under storage from the left-side tree listing.


Right-click on the larger disk icon related to the new hard drive located on the bottom half of the window and select "New Mirrored Volume."


Follow the on-screen instructions to configure the new hard drive to mirror the old hard drive's contents.


  • check The mirrored RAID configuration automatically provides the most up-to-date backup of all the information on the original drive. Data changes apply to both hard drives in a mirrored setup as they happen: any damaging data change like a virus or deleted information will affect both the original drive and the backup. System images create a redundant copy of the hard drive at a specific point in time, which makes them safe from viruses and accidental file deletion. If the origin drive fails or becomes corrupted, you can reinstall Windows from the system image drive to return the computer system to the state when the image was made.
  • check Mirrored hard drives need to have at least the same amount of storage as the original drive. Mirrored hard drives of different sizes will be configured to use the smaller hard drive's maximum capacity.
  • check There are more advanced RAID configurations that can be setup through the system BIOS or during the Windows 8 installation process that offer improved redundancy and faster performance by using three or more hard drives.


  • close While mirrored drives protect the data from hardware failure when one of the drives breaks, it does not protect the data from viruses and accidental deletion.

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About the Author

Dan Stone started writing professionally in 2006, specializing in education, technology and music. He is a web developer for a communications company and previously worked in television. Stone received a Bachelor of Arts in journalism and a Master of Arts in communication studies from Northern Illinois University.

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