Managing Volumes on Dynamic Disks

Any disk using the MBR or GPT partition style can be configured as a dynamic disk. Unlike basic disks, which have basic volumes that can be created as primary partitions, extended partitions, and logical drives, dynamic disks have dynamic volumes that can be created as the following types:

1. Simple volumes: A simple volume is a volume that's on a single drive and has the same purpose as a primary partition. The space allocated for such a volume would be contiguous.
2. Spanned volumes: A spanned volume is a volume that spans multiple drives or can be on a single drive without needing to be contiguous.
3. Striped volumes: A striped volume is a volume that uses RAID 0 to combine multiple disks into a stripe set.
4. Mirrored volumes: A mirrored volume is a volume that uses RAID 1 to mirror a primary disk onto a secondary disk that is available for disaster recovery.
5. RAID-5 volumes: A RAID-5 volume is a volume that uses RAID 5 to create a faulttolerant striped set on three or more disks.

Techniques for creating and managing these volume types are discussed in the sections that follow.

Creating a Simple or Spanned Volume

You create simple and spanned volumes in much the same way. The differences between these volume types are subtle:

• A simple volume uses free space from a single disk to create a volume. Windows is able to write to the selected disk until there is no more free space available within the volume.
• A spanned volume is used to combine the disk space on multiple disks to create the appearance of a single volume. Windows always writes to the first disk in the spanned set first and then when this disk fills, Windows writes to the second disk, and so on.

If you later need more space, you can extend a simple or spanned volume type by using Disk Management. Here, you select an area of free space on any available disk and add it to the volume. When you extend a simple volume onto other disks, it becomes a spanned volume. Any volume that you want to extend should be formatted using NTFS because only NTFS volumes can be extended.

Simple and spanned volumes aren't fault tolerant. If you create a volume that spans disks and one of those disks fails, you won't be able to access the volume. Any data on the volume will be lost. You must restore the data from backup after you replace the failed drive and re-create the volume.

To create a simple or spanned volume, complete the following steps:

1. In Disk Management Graphical View, right-click an area marked Unallocated on a dynamic disk, and then choose New Simple Volume or New Spanned Volume as appropriate. Read the Welcome page and then click Next.
2. If you select New Spanned Volume, you next see the Select Disks page. Use this page to select disks that should be part of the volume and to size the volume segments on the designated disks. Select one or more disks from the list of disks that are available and have unallocated space. Click Add to add the disk or disks to the Selected list box. Next, select each of the disks in turn, then specify the amount of space you want to use on the selected disk. Click Next when you are ready to continue.
   Note: If you started with a dynamic disk, the wizard shows both basic and dynamic disks with available disk space. If you add space from a basic disk that is not a system or boot volume, the wizard will attempt to convert the disk to a dynamic disk before creating the volume set. Before clicking Yes to continue, make sure you really want to do this, as this can affect how the disk is used by the operating system.
3. Use the Assign Drive Letter Or Path page to assign a drive letter or path. You can also choose Do Not Assign A Drive Letter Or Drive Path if you want to create the partition without assigning a drive letter or path. Click Next.
4. Use the Format Volume page, to set the formatting options. Simple and spanned volumes can be formatted by using FAT, FAT32, or NTFS. If you think you might need to extend the volume at a later date, you might want to use NTFS because only volumes using NTFS can be extended. If you opt not to format the partition at this time you can format the partition.
5. Click Next. The final page shows you the options you've selected. If the options are correct, click Finish. The wizard then creates the volume and configures it.