SolutionBase: Managing dynamic disks in Windows XP

Disk drives are becoming ever larger, but data storage needs can quickly outstrip such growth. Here's how you can configure Windows XP's dynamic disk feature to keep the pace.

Windows XP supports two different types of disks: basic disks and dynamic disks. The disk type you use will determine how the physical hard drive space is partitioned and the features that are supported. For example, if you decide to have Windows initialize physical disks as basic disks, you will be able to create primary and extended partitions and logical drives. On the other hand, if disks are initialized as dynamic, you can create simple and spanned volumes and take advantage of additional features.

In this article, I will outline some of the differences between basic and dynamic disks as well as discuss how to manage dynamic disks using the Disk Management console in Windows XP.

Basic vs. dynamic disks

Basic disks are supported by all versions of Windows including Windows 3.x, Windows 9x and Windows NT as well as Windows 2000 and Windows XP. A basic disk supports primary partitions, extended partitions, and logical drives. A basic disk also supports different types of Redundant Array of Independent Disks (RAID) including volume sets, stripe sets, mirror sets, and stripe sets with parity.

Dynamic disks were introduced in Windows 2000 and any earlier versions of Windows do not provide support for this type of disk. Dynamic disks support the following disk configurations:

  • Simple volumes
  • Spanned volumes
  • Mirrored volumes
  • Striped volumes
  • RAID-5 volumes

If you are running Windows 2000 or later, you can use the standard basic disks or convert to dynamic which allows you to take advantage of additional features. When you first install Windows XP Professional (or any other Windows version that supports this disk type), all disks are initialized as basic. Afterwards, you can optionally convert to a dynamic disk using the Disk Management console.

Many people often ask the question "Why convert from basic to dynamic?" The main reason is to take advantage of additional features that include:

  • Disk and volume management tasks can be performed without having to restart the computer afterwards.
  • Volumes that span multiple disks can be created. These are referred to as spanned volumes.
  • A simple or spanned volume can be extended without losing any data.
  • Dynamic disks support an unlimited number (up to 2000) of volumes.
  • Dynamic disks do not use a Master Boot Record (MBR). The disk layout information is stored on the last 1 MB of the disk.

Converting to a dynamic disk

Windows XP allows you to convert from a basic disk to a dynamic disk without losing any data. However, before you attempt to do so, you need to keep the following points in mind:

  • There must be a minimum of 1 MB of free disk space on the master boot record disk you want to convert.
  • Local access to a dynamic disk is limited to Windows 2000 and later.
  • Any partitions on an existing basic disk are converted to simple volumes.
  • You can't revert back to a basic disk without repartitioning.
  • Windows XP Home Edition does not support dynamic disks.
  • Portable computer do not support dynamic disks.
  • As already mentioned, a disk can be converted from basic to dynamic using the Disk Management console. In Windows XP, click Start and click Control Panel. Double click Administrative Tools and open the Computer Management applet. Click Disk Management as shown in Figure A. Right click the disk and click Convert to Dynamic Disk.

    Figure A

    It is important to remember that dynamic disks are not accessible under pre-Windows 2000 operating systems. This is important if you are dual booting with an older version of Windows. Any dynamic disks will not be readable under the legacy version of Windows.

    You should also understand the process for converting back to a basic disk. In order to revert back to a basic disk, you must back up all your data, delete the existing volumes, and repartition the disk. Since the disk has to be repartitioned, your very first step will be to back up all data on the volumes then proceed with the steps below.

    1. Click Start and click Run.
    2. Type mmc and click OK.
    3. Click Add/Remove Snap-in from the File menu.
    4. Click Add. Select Disk Management, click Add then Finish, and click Close.
    5. Click OK.
    6. Click Disk Management (Local) in the left pane.
    7. Right-click a volume on the dynamic disk and click Delete Volume.
    8. Click Yes.
    9. Repeat steps 7 and 8 for each volume on the disk.
    10. Right click the dynamic disk and click Convert to Basic.

    Now that you are familiar with the steps you must complete to convert between basic and dynamic disks, you can begin learning how to manage dynamic disks.

    Managing dynamic disks

    The Disk Management console is the main interface for managing basic and dynamic disks. Once you open the console, you will see a graphical display of all the disks installed on your computer as well as the volumes configured.

    Management tasks can include creating and extending volumes, formatting volumes, changing drives letters, importing disks, and so on. The following sections will discuss how these management tasks can be performed under Windows XP.

    Creating and extending volumes

    The main type of volume on a dynamic disk is a simple volume. You can create a new simple volume or spanned volume within the Disk Management console by completing the steps below:

    1. Right click unallocated space on the dynamic disk and click New Volume. Alternatively, click unallocated space on one of the dynamic disks to create a spanned volume.
    2. Click Next.
    3. Select the type of volume to create: Simple volume or Spanned volume.
    4. Click Next.
    5. Verify that the disk or disks on which you want the volume are selected. Click Next.
    6. Type in the size of the volume. Click Next.
    7. Assign a drive letter to the volume and click Next.
    8. Specify the formatting options. If you choose to format the partition, type in a name for the volume in the Volume Label field and select the file system you want to use. Click Next.
    9. Click Finish.

    Now let's take a look at how to extend a volume. Before outlining the steps there is a VERY important point to keep in mind. A primary partition becomes a simple volume when the disk is converted to dynamic. However, if an existing simple volume was created before the disk was converted to dynamic it can't be extended. A simple volume can only be extended if the simple volume was created after the disk was converted to dynamic. So when you are considering extending an existing volume, remember that a simple volume that was originally a primary partition can't be extended and you can't extend the system or boot volume.

    You can extend a simple volume in Windows XP by following the steps listed below:

    1. Within the Disk Management console, right click the simple of spanned volume that you want to extend. Click Extend Volume.
    2. Select the disk that the volume will be extended to and click Add.
    3. Specify the amount of space to add to the volume. Click Next.
    4. Click Finish.

    Formatting dynamic volumes

    You can use the Disk Management console to format or reformat dynamic volumes. To format a dynamic volume in Windows XP, open the Disk Management console. In the details pane, right click the appropriate volume and click Format. Select the file system you want to use as shown in Figure B and click OK.

    Figure B

    Typically you should choose NTFS over FAT32 because of the additional features it supports such as file level security, disk compression, file encryption, and disk quotas. Windows XP includes support for FAT and FAT32 to remain compatible with older operating systems since anything pre-Windows NT 4.0 do not support NTFS. In most cases the only time you would want to use FAT or FAT32 if for multi boot configurations where you have Windows XP and an older operating system, such as Windows 98, running on the same system. However, remember that these older versions of Windows can't access a Dynamic Volume anyway, so there's little point in using FAT or FAT32.

    Changing the drive letter assigned to a dynamic volume

    Before you go ahead and start changing the drive letters, you need to keep two important points in mind. First of all, the Disk Management console can't be used to change the drive letter assigned to the system or boot volume. Second, some MS-DOS and older Windows programs refer to specific drive letters for environmental variables. Therefore, altering the drive letters may cause some of these programs not to function correctly.

    With those points in mind, you can change the drive letter currently assigned to a volume within the Disk Management console by right clicking the appropriate volume and clicking Change Drive Letter and Paths. Click Change as shown in Figure C. Use the drop down arrow to select the drive letter you want to use. Click OK and click Yes when prompted to confirm your actions. The new drive letter you selected will now be assigned to the volume.

    Figure C

    Importing dynamic disks

    One of the perks of using dynamic disks is that you can move physical disks between computers. A dynamic disk will have a status of foreign when it is moved from one computer to another. You will be unable to access any data on the disk until it is imported into the computer's system configuration.

    If you have moved a dynamic disk from one computer to another, you can use the steps below to import it. The steps below assume that you have already physically added the foreign disk to the computer.

    1. Click Start and click Run.
    2. Type mmc and click OK.
    3. Click Add/Remove Snap-in from the File menu.
    4. Click Add. Select Disk Management, click Add then Finish, and click Close.
    5. Click OK.
    6. Click Disk Management (Local) in the left pane.
    7. From the Action menu, click Rescan Disks.
    8. Right click the disk marked as Foreign and click Import Foreign Disks.
    9. Follow the onscreen instructions to complete the process.

    You should now be able to access the data that is stored on the new disk. Remember that any time you remove or add a physical type to a computer you have to open the Disk Management console and select the Rescan Disks option from the Action menu.