Set Up Storage Spaces Mirror in Windows 10/11 for Local Redundancy

Set Up Storage Spaces Mirror in Windows 10/11 for Local Redundancy​

Difficulty: Intermediate | Time Required: 30-45 minutes

Introduction​

Storage Spaces is a built-in Windows feature that lets you group two or more physical drives into a single virtual pool and create resilient storage volumes. Creating a "two-way mirror" provides local redundancy by keeping two copies of your data across different physical disks — if one disk fails, your files stay intact. This is a great lightweight way to protect important data on a single PC without buying a hardware RAID controller.

Prerequisites​

• Windows 10 (Version 1809 and later) or Windows 11. The Storage Spaces UI exists in both; advanced ReFS support is limited to certain SKUs (Windows 10/11 Pro for Workstations and Server editions).
• At least two separate physical drives (HDD/SSD). For a two-way mirror, minimum = 2 drives. For a three-way mirror, minimum = 3 drives.
• All data on the drives you add to the pool will be erased. Back up any important data before continuing.
• Administrative privileges on the PC.
• Recommended: drives of similar capacity and performance. Avoid using USB drives that may disconnect frequently — internal SATA/NVMe or externally always-on enclosures are preferred.

Step-by-step instructions (GUI)​

1. Connect and power on all drives you plan to use. Make sure Windows detects them (open Disk Management to confirm: Win+X → Disk Management).
2. Open Storage Spaces:
   • Windows 10: Control Panel → System and Security → Storage Spaces.
   • Windows 11: Press Start → type “Storage Spaces” → choose the Storage Spaces control panel entry. (You can also search Settings → System → Storage → Advanced storage settings → Manage Storage Spaces.)
3. Click “Create a new pool and storage space.”
4. Select the physical drives you want to add to the pool. Carefully confirm you chose the correct drives — all selected drives will be erased. Click “Create pool.”
   • Warning: This deletes existing partitions and data on the selected drives.
5. On the “Create a storage space” screen:
   • Name the storage space (Friendly name).
   • Assign a drive letter if desired.
   • Choose the Resiliency type:
     • Select “Two-way mirror” for two-copy redundancy (recommended for most home/office users).
     • “Three-way mirror” gives higher redundancy but requires more disks and space.
   • Choose a File system:
     • NTFS is recommended for broad compatibility.
     • ReFS may be available on certain Windows editions (Pro for Workstations / Server). Use ReFS only if you understand the limitations.
   • Set the size (capacity). You can set a larger “logical” size than the physical pool (thin provisioning), but be cautious — running out of physical capacity can cause problems.
6. Click “Create storage space.” Windows will create the virtual disk, initialize and format it, and mount it as a drive letter.
7. After creation, the new mirrored volume appears in File Explorer. Move or copy your important data onto it.

Step-by-step instructions (PowerShell — advanced)​

Note: PowerShell gives more control and is useful for automation or when the UI is unavailable.

1. Open PowerShell as Administrator.
2. See available physical disks:
   • Get-PhysicalDisk | Where-Object CanPool -eq $True
3. Create a new storage pool:
   • $pool = New-StoragePool -FriendlyName "MyPool" -StorageSubsystemFriendlyName "Storage Spaces*" -PhysicalDisks (Get-PhysicalDisk -CanPool $True | Select -First 2)
     (Adjust selection to the disks you want.)
4. Create a mirrored virtual disk:
   • New-VirtualDisk -StoragePoolFriendlyName $pool.FriendlyName -FriendlyName "MirrorVD" -ResiliencySettingName Mirror -Size 2TB
     (For a two-way mirror, set -ResiliencySettingName Mirror. Adjust size.)
5. Initialize disk and create partition/format:
   • $vd = Get-VirtualDisk -FriendlyName "MirrorVD"
   • $vd | Get-Disk | Initialize-Disk -PassThru | New-Partition -UseMaximumSize -AssignDriveLetter | Format-Volume -FileSystem NTFS -NewFileSystemLabel "MirrorVol" -Confirm:$false

Tips, warnings, and notes​

• WARNING: Creating a pool erases all data on the selected drives. Back up before you start.
• Don’t mix very slow or unreliable USB drives with faster internal drives — temporary disconnections can cause the pool to go read-only or lose resiliency.
• Two-way mirror protects against a single disk failure (one physical disk can fail). It is not a replacement for offsite or versioned backups — accidental deletion or ransomware can still affect all copies.
• Consider using drives slightly larger than your intended pool size to avoid running into capacity shortages.
• Thin provisioning is convenient but monitor actual capacity closely: Storage Spaces won’t let you write beyond the physical capacity if you exhaust the pool.
• If you need maximum uptime and redundancy in a desktop environment, consider at least a three-way mirror (requires 3+ disks) or use a dedicated NAS or server with better redundancy options.
• ReFS is resilient against data corruption, but native ReFS support in client Windows editions is limited — check your edition before choosing it.

Troubleshooting​

• The pool shows “READ-ONLY” or “Degraded”:
  • Open Storage Spaces → the pool → check physical disks. A disk likely shows as “Lost” or “Retired.”
  • If a disk failed, replace it with a new physical disk of equal or larger size and use the UI or PowerShell to add the disk to the pool and repair the virtual disk.
  • PowerShell helpful commands: Get-StoragePool, Get-PhysicalDisk, Repair-VirtualDisk -FriendlyName "MirrorVD"
• Disk not available in pool creation:
  • If a disk is partitioned/initialized, you may need to delete partitions in Disk Management or use Clear-Disk -RemoveData -Confirm:$false in PowerShell (will erase data).
• Performance concerns:
  • Mirroring increases writes (duplication). Use SSDs or fast HDDs for better performance, and ensure cables/controllers are healthy.
• If a disk was accidentally removed or the pool won’t mount:
  • Reboot, check BIOS/UEFI for drive detection, confirm cables and power. If still problematic, consult the Windows event logs and Storage Spaces health info.

Conclusion​

Setting up a Storage Spaces two-way mirror in Windows 10/11 gives you straightforward, built-in local redundancy without extra hardware and is suitable for protecting important files from single-disk failures. It’s quick to set up, flexible, and manageable from both the GUI and PowerShell. Remember that Storage Spaces protects against disk failure, not accidental deletion, corruption, or disasters — so combine it with regular, offsite/versioned backups for a complete strategy.
Key Takeaways:

• Storage Spaces two-way mirror maintains two copies of data across disks for single-disk failure protection.
• Requires at least two physical disks; all disks added will be erased during pool creation—backup first.
• Use NTFS for compatibility; ReFS is limited to certain editions.
• Not a substitute for offsite or versioned backups — still perform regular backups.

---

This tutorial was generated to help WindowsForum.com users get the most out of their Windows experience.