Configuring a software mirror (RAID) on Windows

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KB0057464

Configuring a software mirror (RAID) on Windows


Icons/System/eye-open Created with Sketch. 7691 Ansichten 28.03.2023 Cloud / Dedicated Server (Bare Metal)

Objective

On a Windows system, data redundancy is achieved by mirroring the primary disk to a second one. This is similar to a RAID 1 configuration but only involves two disks.

This guide explains how to reconfigure the disk mirror of your Windows system if it needs to be rebuilt due to corruption or disk failure.

Requirements

  • A Windows dedicated server with a software mirror
  • Administrative access to the server via RDP

Instructions

Establish a remote desktop (RDP) connection to your server.

Once logged in, right-click on the Start Menu button and open Run.

Software mirror Windows

Enter "cmd" and click on OK.

Software mirror Windows

The method to use depends on the partition style of your disks. Follow the instructions in this section for MBR or skip to the subsequent section for GPT. If you are unsure, run diskpart at the command prompt and enter list disk. Check the "Gpt" column in the output.

Rebuilding the mirror (MBR partion scheme)

At the command prompt, open DiskPart:

C:\Windows\system32> diskpart

DiskPart executes commands without issuing warnings or asking for confirmation. Any changes done in DiskPart are irreversible. Entering commands while the wrong disk or volume is selected may therefore cause immediate data loss and/or prevent your system from booting. We recommend to proceed with caution and double-check each command.

Listing all disks and volumes

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          447 GB      0 B   *
  Disk 1    Online          447 GB   447 GB
  Disk M0   Missing            0 B      0 B   *

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Mirror       447 GB  Failed Rd  System

In this example, Disk 1 is a replacement drive that has been installed in order to replace the defective Disk M0 which had been physically removed previously.

The following code sections are for the purpose of illustration only, based on the example output above. You will need to adjust the instructions according to your actual configuration by replacing the values in the commands with your disk and volume identifiers.

Removing the replaced disk from the configuration

DISKPART> select volume c

Volume 0 is the selected volume.

DISKPART> break disk M0 nokeep

DiskPart successfully broke the mirror volume.

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Simple       447 GB  Healthy    System

DISKPART> select disk m0

Disk M0 is now the selected disk.

DISKPART> delete disk

DiskPart successfully deleted the missing disk.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---s
  Disk 0    Online          447 GB      0 B   *
  Disk 1    Online          447 GB   447 GB

Initialising the replacement disk

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> convert mbr

DiskPart successfully converted the selected disk to MBR format.

DISKPART> convert dynamic

DiskPart successfully converted the selected disk to dynamic format.

Recreating the mirror between the first and the second disk

DISKPART> select volume c

Volume 0 is the selected volume.

DISKPART> add disk 1

DiskPart succeeded in adding a mirror to the volume.
<===>

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
* Disk 0    Online          447 GB      0 B   *
  Disk 1    Online          447 GB      0 B   *

Repeat this step for each existing volume from Disk 0 that you want to mirror on Disk 1, using the associated drive letter (i.e. d, e, f, etc.).

The volume state will be Rebuild during the process, which may take several hours depending on the data stored on the disk. You can check the status in DiskPart:

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
* Volume 0     C   Windows      NTFS   Mirror       447 GB  Rebuild    System

It is best not to restart the server until the rebuild process is complete.

Rebuilding the mirror (GPT partition scheme)

At the command prompt, open DiskPart:

C:\Windows\system32> diskpart

DiskPart executes commands without issuing warnings or asking for confirmation. Any changes done in DiskPart are irreversible. Entering commands while the wrong disk or volume is selected may therefore cause immediate data loss and/or prevent your system from booting. We recommend to proceed with caution and double-check each command.

Listing all disks and volumes

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online         1863 GB      0 B   *    *
  Disk 1    Online         1863 GB  1863 GB
  Disk M0   Missing           0  B      0 B   *   


DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Mirror      1862 GB  Failed Rd  Boot
  Volume 1         EFI          FAT32  Partition    350 MB  Healthy    System

In this example, Disk 1 is a replacement drive that has been installed in order to replace the defective Disk M0 which had been physically removed previously.

The following code sections are for the purpose of illustration only, based on the example output above. You will need to adjust the instructions according to your actual configuration by replacing the values in the commands with your disk and volume identifiers.

Removing the replaced disk from the configuration

DISKPART> select volume c

Volume 0 is the selected volume.

DISKPART> break disk M0 nokeep

DiskPart successfully broke the mirror volume.

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Simple      1862 GB  Healthy    Boot
  Volume 1         EFI          FAT32  Partition    350 MB  Healthy    System

DISKPART> select disk M0

Disk M0 is now the selected disk.

DISKPART> delete disk

DiskPart successfully deleted the missing disk.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online         1863 GB      0 B   *    *
  Disk 1    Online         1863 GB  1863 GB

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Simple      1862 GB  Healthy    Boot
  Volume 1         EFI          FAT32  Partition    350 MB  Healthy    System

Initialising the replacement disk

On the new disk, create default and mandatory partitions, reflecting the existing partitioning of the first disk:

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> clean

DiskPart succeeded in cleaning the disk.

DISKPART> convert gpt

DiskPart successfully converted the selected disk to GPT format.

DISKPART> select partition 1

Partition 1 is now the selected partition.

DISKPART> delete partition override

DiskPart successfully deleted the selected partition.

DISKPART> create partition efi size=350

DiskPart succeeded in creating the specified partition.

DISKPART> format quick fs=fat32 label=EFI

  100 percent completed

DiskPart successfully formatted the volume.

DiskPart successfully formatted the volume.

DISKPART> assign letter=t

DiskPart successfully assigned the drive letter or mount point.

DISKPART> create partition msr size=128

DiskPart succeeded in creating the specified partition.

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    System             350 MB  1024 KB
* Partition 2    Reserved           128 MB   351 MB

Recreating the mirror between the first and the second disk

DISKPART> select volume c

Volume 0 is the selected volume.

DISKPART> add disk 1

DiskPart succeeded in adding a mirror to the volume.

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
* Disk 0    Online         1863 GB      0 B   *    *
  Disk 1    Online         1863 GB      0 B   *    *

Repeat this step for each existing volume from Disk 0 that you want to mirror on Disk 1, using the associated drive letter (i.e. d, e, f, etc.).

Recreating the boot environment and setting boot options for the second disk

DISKPART> select disk 0

Disk 0 is now the selected disk.

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    System             350 MB  1024 KB
  Partition 2    Dynamic Reserved  1024 KB   351 MB
  Partition 3    Reserved           127 MB   352 MB
  Partition 4    Dynamic Data      1862 GB   479 MB
  Partition 5    Dynamic Data        71 KB  1863 GB

DISKPART> select partition 1

Partition 1 is now the selected partition.

DISKPART> assign letter=s

DiskPart successfully assigned the drive letter or mount point.

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Mirror      1862 GB  Rebuild    Boot
* Volume 1     S   EFI          FAT32  Partition    350 MB  Healthy    System
  Volume 2     T   EFI          FAT32  Partition    350 MB  Healthy    Hidden

DISKPART> exit

Leaving DiskPart...

Back at the command prompt, copy the boot files from the boot (EFI) partition on first disk (Disk 0) to the boot partition on the second disk (Disk 1).

Type the following 3 commands and execute each one with Enter:

robocopy s:\ t:\ * /e /copyall /xf BCD.* /xd "System Volume Information"
bcdedit /export t:\EFI\Microsoft\Boot\BCD
bcdedit /store t:\EFI\Microsoft\Boot\BCD /set {bootmgr} device partition=t:

Then launch DiskPart again and run the following commands:

DISKPART> select volume s

Volume 2 is the selected volume.

DISKPART> remove

DiskPart successfully removed the drive letter or mount point.

DISKPART> select volume t

Volume 1 is the selected volume.

DISKPART> remove

DiskPart successfully removed the drive letter or mount point.

The volume state will be Rebuild during the process, which may take several hours depending on the data stored on the disk. You can check the status in DiskPart:

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     C   Windows      NTFS   Mirror      1862 GB  Rebuild    Boot
  Volume 1         EFI          FAT32  Partition    350 MB  Healthy    Hidden
  Volume 2         EFI          FAT32  Partition    350 MB  Healthy    System

It is best not to restart the server until the rebuild process is complete.

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