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How to set up a mirrored volume for file redundancy on Windows 10

It's not a matter of "if," it's a matter of "when." Sooner or later the hard drive on your computer will die, and the odds are that you will lose all your files stored on that drive.

Of course, there is a number of ways to prevent data loss. You can, for example, keep a current backup of your computer, you can make copies of your files to an external drive, or you can store your data in the cloud. However, similar to previous versions, Windows 10 includes a feature that let you mirror the data on one drive into another to offer data protection from a drive failure.

In Windows, we call the feature "mirror," but the concept actually comes from the standard RAID levels, which define a number of techniques to combine multiple hard drives to offer speed, redundancy, or performance.

On the standard RAID levels, "mirror" is defined as RAID 1, and it consists of having an exact bit-to-bit replica of the data in another hard drive. Usually, a mirror setup contains two hard drives, but you can always add more, as long you add them in pairs.

In this Windows 10 guide, we'll walk you through the steps to create a mirrored volume on your computer to protect your data from drive failure.

Details before beginning

Before we dive in this guide, it's important to note that to create a mirrored volume on Windows 10, or with any operating system, you'll need at least two physical hard drives. Your second drive should be at least the same size as the original (a larger second drive is okay).

How to create a new mirrored volume

The instructions described below are to create a brand new mirrored volume where neither hard drive have any data.

To create a mirrored volume, do the following:

  1. Use the Windows key + X keyboard shortcut to open the Power User menu and select Disk Management.
  2. Right-click one of the empty drives, and select New Mirrored Volume.

  1. Click Next.
  2. Select the available drive from the left.
  3. Click Add.
  4. Specify the amount of space for the mirrored volume.Important: The volume cannot be larger than the amount of the available space in the smaller hard drive, as you can't mirror data to space you don't have.
  5. Click Next.

  1. Assign a drive letter or leave the default settings and click Next.
  2. Select Format this volume with the following settings option making sure file system is set to NTFS, allocation unit size is set to default, and you enter a name for the volume.
  3. Check the Perform a quick format option.
  4. Click Next.

  1. Click Finish.
  2. Click Yes to convert the basic disks to dynamic disks, which is a requirement to create a mirrored volume on Windows.

Once the process completes, you'll only see one volume created, and as you store content on the new volume, the data will also automatically get replicated into the secondary drive.

How to create a mirrored volume with data already in the drive

The following instructions explain the steps to set up a mirrored volume when one of the drives already have data on it.

To create a mirrored volume with data already in the drive, do the following:

  1. Use the Windows key + X keyboard shortcut to open the Power User menu and select Disk Management.
  2. Right-click the primary drive with data on it, and select Add Mirror.

  1. Choose the drive that will act as a duplicate.
  2. Click Add Mirror.

  1. Click Yes to convert the basic disks to dynamic disks, which is a requirement to create a mirrored volume on Windows.

After completing the steps above, Windows 10 will synchronize the data on the primary drive to the second drive. This process can take a long time depending on the data you have stored in the volume.

How to recreate a mirror after drive failure

Once you set up a mirror, if either hard drive fails, you'll still be able to access your data. However, it's highly recommended that you replace the drive as soon as possible.

To recreate a mirror after a drive failure, do the following:

  1. Use the Windows key + X keyboard shortcut to open the Power User menu and select Disk Management.
  2. Right-click the hard drive in working conditions on the mirror and select Remove Mirror.

  1. Select drive labeled Missing.
  2. Click Remove Mirror.

  1. Click Yes.
  2. Right-click the primary drive with data on it, and select Add Mirror.

  1. Select the new drive that will act as a mirror.
  2. Click Add Mirror.

  1. Click Yes to convert the basic disks to dynamic disks, which is a requirement to create a mirrored volume on Windows.

After completing the steps above, Windows 10 will synchronize the data onto the new drive. Then simply repeat the process whenever a drive fails (which hopefully shouldn't be very often).

Wrapping things app

The primary purpose of a mirror setup is to provide data redundancy to protect your files from a hard drive failure. It's not designed to offer speed or performance like other RAID array levels.

Although mirroring can protect your data, it's not a replacement for a data backup. If you accidentally delete a file from one drive, the action will also replicate to the second drive.

Finally, it's worth pointing out that thanks to the Windows 10 flexibility, you can also use Storage Spaces to create a mirrored volume.

Do you use any form of file redundancy on your computer? Tell us in the comments below.

More on Windows 10 resources

For more tips, coverage, and answers on Windows 10, you can visit the following resources:

Mauro Huculak is technical writer for WindowsCentral.com. His primary focus is to write comprehensive how-tos to help users get the most out of Windows 10 and its many related technologies. He has an IT background with professional certifications from Microsoft, Cisco, and CompTIA, and he's a recognized member of the Microsoft MVP community.

33 Comments
  • Nice but I have 1tb one drive, with date I want backed up
  • Where did they find 7 GB drives for this tutorial?
  • It's probably a virtual machine with virtual disks. But good catch!
  • I have quite a few >20 GB hard drives in my obsolete parts collection. The bigger question would be, what users IDE anymore? =P
  • Nothing lasts forever !
  • Or you could use Storage Spaces?
  • Right? Considering this tutorial is meant for users of Windows 10, seems odd that it would not at least mention Storage Spaces, which is way better than the dynamic disks of yore. Maybe they went this way because Storages Spaces doesn't work with boot drives.
  • Storage spaces has complications when it comes to replacing/adding drives, it's actually more straightforward to go with the simple soft raid approach in this guide.
  • Not at all! If you're doing a simple mirror with Storage Spaces, it's a lot simpler than this.
  • saw these exact same steps and images on another website...just sayin
  • I avoid using dynamic disks because it makes them harder to work with when using recovery tools on them. Only reason to convert your basic disks to dynamic is only for this type of thing. Once it's dynamic, you can't go back to basic. A lot of recovery software can't detect or work with dynamic disks. I feel that there are better alternatives to save yourself the headaches. Posted via the Windows Central App for Android
  • Does Storage Spaces convert the disks to dynamic do you know?
  • No, it uses ReFS, which is something completely different.
  • If using their version of RAID 1 does it alter the discs in a way that prevents just switching them out to another machine or how easy it is to recover data down the line?
  • Storage Spaces (and ReFS), no matter what mode (mirror, parity, or just a pool with no redundancy) can be moved between systems just as easily as you could move an NTFS-formatted drive. Obviously, the system must be Windows 8/8.1/10 (or their Server equivalent), but there's nothing stopping you from moving drives between systems. Because ReFS is relatively new, both of drives in a mirror were to fail simultaneously, it might be tougher to do a low-level recovery than it would be with NTFS. However, because ReFS is more "resilient" by design, you're theoretically less likely to encounter data corruption problems in the first place.
  • I prefer to just use imaging software to make regular backups. Every 3 days my system drive gets backed up, and once a week I backup the data partition
  • Depending on the imaging software you can get some nice compression too!
  • Good topic, but I should think that Storage Spaces should probably be the first option considered by Windows 10 users. You might have mentioned this at the top of the article, instead of the end.
  • Can you do this with an external or network drive? Or this more like traditional RAID and controlled via the MB or RAID controller?
  • I use file history to my C and D drive on E
  • Mirrored disks protect against failed disks. File history protects against deleted files.
  • Yes with mirrored disks the data will be deleted from both right away.
  • I've been meaning to do this but keep forgetting. I already have a mirrored external drive. Since an SSD is more reliable than a spinning disk, I have been thinking about replacing my main single hard drive with two SSDs instead of just using my small SSD for the OS.
  • More disks or NAS and RAID 10 (1+0) 
  • Storage spaces is the better method for this
  • Correction: Article title should say "disk redundancy" instead of "file redundancy".
  • Not that this is a bad idea, but this methodology does not protect against:
    1) Theft of the device.
    2) Significant damage to the device including both drives
    3) Severe viral infections that may damage, delete, or encrypt files
    4) Microsofts own barrage of messed up updates that corrupt systems.  Me and other IT pros have been having a heck of a time in recent weeks with numerous issues related to WSUS, corrupted upgrades, corrupted user profiles, etc. I've never really been a fan of RAID, and don't use it in my office network.  Instead I use full disk backups of all servers and mission-critical PCs.  I also have "master" PC that can be used as a source for the latest disk images for use on other PCs in the office.  Everything is backed up to a roation of 2TB drives, one for each day of the week.  Each drive holds two days worth of backups, so at any given time I have 10 business days worth of images that I can restore form, or extract qaccidently deleted/overwritten files from.  All that is beyond the home user. But at any rate, I think a better option for many home users is to leverage disk backups to external drives (or home NAS or a large USB thumb drive) that can then be stored/secured elsewhere, or leverage cloud backup (if you have the luxury of time to restore from there).  A 2TB USB 3.0 external drive can be had for less than $100 these days (meaning it's not much more than buying a second drive for the PC in the first place), and periodic baclkups can be done using that.  Maybe a full disk image weekly or even monthly, and a profile/docs/email backup daily.
     
  • First, lets get this out of the way. Yes, RAID is not a backup, and you should be keeping backups. But in the spirit of this article (and what most people seem to do in instead of keeping backups), here is my experience with Storage Spaces. I actually switched from Storage Spaces to a mirrored volume on dynamic disks after almost losing all of my data. Out of a mirrored pool of two, one disk started to fail. Storage Spaces incorrectly marked the working disk as Unhealthy, and eventually Retired it. Once a disk is marked Retired, there is no way I could find to reverse that status, short of wiping the drive. With the other drive actually failing, I was left with trying to recover data from the "Retired" drive. I found that Storage Spaces volumes were so different from typical mirrors, that my existing file recovery software won't work. Thankfully I was able to recover my data after purchasing ReclaiMe File Recovery, which is the only product capable of recovering data from a Storage Spaces volume as of a year ago. If you are supporting a medium sized business and need large arrays of disks with parity, Storage Spaces is a better option than using Disk Management mirrored disks. For home users however, I would not recommend using Storage Spaces unless you work in an area of IT where you regularly work with Storage Spaces, or you have a large array of disks AND are willing to keep backups AND are willing to learn not just how to set up Storage Spaces but also administer it. In spite of what evangelists say, Storage Spaces is not simple.
  • This discusses only software mirroring with Windows. Doing it outside the OS with a proper RAID controller is another thing to consider.
  • Is it possible to mirror a folder and all files and sub-folders in it? Anyone knows? Posted via the Windows Central App for Android
  • Doesn't the old app sync toy do this?
  • I want to replace my old HDD with an SSD. Is mirroring an option to make the SSD an exact copy of my old HDD so I can replace my old drive without setting up my computer from the beginning?
  • How well does this work with external hard drives that are often removed from the system?