diskpart and mirrored volume

Create a mirrored volume

Create and test a mirrored system or boot volume

Create or break a mirrored boot volume

Add a mirror to an existing simple volume

Break a mirrored volume into two volumes

Remove a mirror from a mirrored volume

Reconnect the disk and repair the mirrored volume

Reactivate a mirrored volume

Replace a failed mirror with a new mirror on 

To create a mirrored volume

• You need two dynamic disks to create a mirrored volume.
• You can mirror an existing simple volume.
• Mirrored volumes are fault tolerant and use RAID-1, which provides redundancy by creating two identical copies of a volume.
• Mirrored volumes cannot be extended.
• Both copies (mirrors) of the mirrored volume share the same drive letter.
• You can create mirrored, striped, spanned and RAID-5 volumes using a combination of MBR and GPT disks, but the MBR cylinder-alignment restriction may cause some difficulties in creating mirrored volumes. Always mirror the MBR disk to the GPT disk to avoid cylinder-alignment difficulties.

1. Open Command Prompt.
   
2. Type: diskpart
3. At the DISKPART prompt, type:list diskMake note of the disk numbers for the dynamic disks that will make up the mirrored volume.
4. At the DISKPART prompt, type:select disk n
5. At the DISKPART prompt, type:create volume simple [size=n] [disk=n]
6. At the DISKPART prompt, type:add disk n

create volume simple	Creates a simple volume. After you create the volume, the focus automatically shifts to the new volume.
size=n	The size of the volume in megabytes (MB). If no size is given, the new volume takes up the remaining free space on the disk.
disk=n	The dynamic disk on which to create the volume. If no disk is given, the current disk is used.
add disk=n	Mirrors the simple volume with focus to the specified disk, where n is the disk number. The specified disk must have unallocated space at least as large as the size of the simple volume you want to mirror.

To break a mirrored volume into two volumes

1. Open Command Prompt.
   
2. Type: diskpart
3. At the DISKPART prompt, type:
   list volume
   Make note of the number of the mirrored volume.
   
4. At the DISKPART prompt, type: select volume n
5. Select the mirrored volume you want to break into two separate volumes.
6. At the DISKPART prompt, type:
   detail volume
   Make note of the disk number of the mirrored volume you want to break into two separate volumes.
7. At the DISKPART prompt, type:
   break disk n

Remove a mirror from a mirrored volume

Using a command line

1. Open Command Prompt.
   
2. Type:
   diskpart
   
3. At the DISKPART prompt, type:
   list volume
    Make note of the volume number of the mirrored volume.
   
4. At the DISKPART prompt, type:
   select volume n
   
5. At the DISKPART prompt, type:
   detail volume
    Make note of the disk number that specifies the half of the mirrored volume you want to remove and convert to free space.
   
6. At the DISKPART prompt, type:
   break disk n [nokeep]

break disk n

Applies to dynamic disks only. Breaks a mirrored volume into two simple volumes. These volumes are no longer fault tolerant. The disk specified by n receives the focus so you can assign it a drive letter. If the specified disk is the current system or boot disk, the command fails. The other disk retains the drive letter and any mount points that belonged to the mirrored volume. Using the nokeep parameter, the specified disk, n, is deleted and converted to free space, while the other half of the mirror is retained as a simple volume. Neither volume receives focus.

Nokeep

Specifies that only one of the mirrored volumes retained; the other simple volume is deleted and converted to free space. Neither volume receives the focus.

ImportantOnce you remove a mirror from a mirrored volume, the removed mirror becomes unallocated space and the remaining mirror becomes a simple volume that is no longer fault tolerant. All of the data on the removed mirror is deleted.