Windows 7 / Getting Started

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Working with Dynamic Disks

When you convert a basic disk to a dynamic disk, the existing partitions are converted to simple volumes and fault-tolerant volumes are converted into dynamic volumes. Dynamic volumes can be changed on the fly, as the name dynamic implies. A dynamic volume is a unit of storage initially created from the free space on one or more disks. Table below lists the volume types available on a dynamic disk.

Dynamic Volume Types

Volume Type	Number of Disks	Configuration	Fault Tolerance
Simple	1	A single region or multiple concatenated regions of free space on a single disk.	None
Spanned	2-32	Two or more regions of free space on 2-32 disks linked into a single volume. Can be extended. Cannot be mirrored.	None
Striped	2-32	Multiple regions of free space from two or more disks. Data is evenly interleaved across the disks, in stripes. Known as RAID Level 0.	None
Mirrored	2	Data on one disk is replicated on the second disk. Cannot be extended. Known as RAID Level 1.	Yes, with maximum capacity of the smallest disk
RAID-5	3-32	Data is interleaved equally across all disks, with a parity stripe of data also interleaved across the disks. Also known as striping with parity.	Yes, with maximum capacity of the number of disks minus one (if you have five 200 GB disks, your volume would be 800 GB)

Creating a simple volume on a dynamic disk proceeds exactly as already described for creating a partition on a basic disk. As with basic disks, you can also extend, shrink, or delete a volume. We look at the methods of creating and working with striped, mirrored, and RAID-5 volumes later in this tutorial.

Dynamic volumes allow you to change their properties on an as-needed basis. If you have a computer that is, for example, running short of space, you can install an extra hard drive and extend an existing simple or spanned volume so that the new space is immediately available without directing the user to use drive J for this data, drive C for that data, drive Y for the network, and so on. Users find multiple drive letters confusing, so being able to keep it all under one letter is highly preferable. Unfortunately, you cannot extend a system volume or a boot volume. Because most computers are installed with a single volume, C:, which includes boot and system files, any volumes created on a new disk added to the computer must have a separate drive letter from the C: drive.

To increase the size of a simple volume, in Disk Management, right-click the existing volume and select Extend Volume from the shortcut menu. The Extend Volume Wizard starts and you are prompted to select the disk or disks that contain the free space you will be adding. After you specify the size of free space to add, you need to confirm your options and click Finish. The volume is extended and appears in the Disk Management window with new space allocated to it.

The Disk Management utility is fairly comprehensive, but it is not the only tool available in Windows 7 to configure or manage disks. Some of these tools hearken back to the days of DOS and Windows 3.x, yet they are still very useful, especially if there is a problem accessing the graphical user interface (GUI):

• Chkdsk.exe: A command-line utility that verifies and repairs FAT- or NTFSformatted volumes. (For NTFS drives, use the CHKDSK C: /R command to automatically check and repair disk problems.)
• Cleanmgr.exe: Also known as Disk Cleanup, a GUI utility that deletes unused files.
• Defrag.exe: Also known as Disk Defragmenter, a command-line utility that rearranges files contiguously, recapturing and reorganizing free space in the volume. Optimizes performance.
• DiskPart.exe: A command-line utility that can run a script to perform diskrelated functions. DiskPart's nearest GUI counterpart is the Disk Management utility.
• Fsutil.exe: A command-line utility that displays information about the file system and can perform disk-related functions.