Converting Disks

Converting a Disk from Basic to Dynamic

The Windows Server Disk Management console (an MMC snap-in) can be used to convert a basic disk to a dynamic disk. To access Disk Management, click Start > Administrative Tools > Computer Management or right-click the My Computer icon on the Start menu and click Manage.

You must be a member of the local Administrators group or the Backup Operators group, or else the have proper authority delegated to you if you are working to make any changes to the computer’s disk-management configuration within an Active Directory environment.

Any disks to be converted must contain at least 1MB of unallocated space. Disk Management automatically reserves this space when creating partitions or volumes on a disk, but disks with partitions or volumes created by other operating systems or third-party utilities might not have this space available.

Windows Server needs this disk space to store the dynamic database, which is maintained by the operating system that created it. Before converting any disks, close any programs that are running on them. After converting a disk to dynamic, remember that you can only have one bootable operating system on each dynamic disk.

You can convert a basic disk to a dynamic disk from the Disk Management console as follows:

  1. Open the Disk Management console.
  2. Right-click the basic disk you that want to convert to a dynamic disk and then click Convert to Dynamic Disk.

If you convert an empty basic disk to a dynamic disk, you do not need to reboot. However, if you convert a basic disk that already has partitions on it, or if the basic disk contains the system or boot partitions, you must reboot.

Converting from the Command Line

You can convert a basic disk to a dynamic disk from the Windows Server command line as follows:

  1. Open a command prompt window, type diskpart, and press Enter.
  2. Type commands or help to view a list of available commands.
  3. Type select disk 0 to select the first hard disk, select disk 1 to select the second hard disk etc. and press Enter.
  4. Type convert dynamic and press Enter.
  5. Type exit to quit diskpart.exe, then restart the computer to have the new configuration take effect.

When you convert a basic disk to a dynamic disk, any existing partitions on the basic disk become simple volumes on the dynamic disk. Any existing mirror sets, stripe sets, stripe sets with parity or volume sets become mirrored volumes, striped volumes, dynamic RAID-5 volumes or spanned volumes, respectively. Once you convert a basic disk to a dynamic disk, you cannot change the volumes back to partitions. Instead, you must first delete all dynamic volumes on the disk, right-click the disk in Disk Management, and then select the Convert to Basic Disk option.

Because the conversion process from basic to dynamic is per physical disk, a disk will have all dynamic volumes or all basic partitions. You do not need to reboot when you upgrade from an empty basic to a dynamic disk from the Disk Management console, but you do have to restart your computer if:

  • you use the diskpart.exe command-line tool for the conversion
  • you convert a disk containing the system volume, boot volume, or a volume with an active paging file
  • the disk contains any existing volumes or partitions.

Converting from Dynamic to Basic

Converting to a dynamic disk is intended to be a one-way process. It is only possible to convert a dynamic disk back to a basic disk at the expense of losing all your data. If it is necessary to convert a dynamic disk back to a basic disk you should back up your data and delete all the volumes on the disk. You can then convert the disk to basic and restore your data.

You must remove all volumes (and therefore all data) from a dynamic disk before you can change it back to a basic disk. After you convert a dynamic disk back to a basic disk, you can only create partitions and logical drives on volumes, striped volumes, dynamic RAID-5 volumes, or spanned volumes, respectively.

To convert a dynamic disk back to a basic disk, perform the following steps:

  1. Back up the data on the dynamic disk.
  2. Open Disk Management.
  3. Delete all the volumes on the disk.
  4. Right-click the dynamic disk that you want to change back to a basic disk and then click Convert to Basic Disk.
  5. Restore the data to the newly converted basic disk.

Next: Foreign Disks