Virtual Disk Service and Its Client Tools

Windows 2003's VDS and its client tools provide one interface for storage devices


In April 2002, Microsoft appointed Bob Muglia senior vice president of the newly formed Enterprise Storage Division. At that time, Muglia described the technology plans that would make Windows act as a hub for managing data across PCs, servers, and storage systems and said Microsoft would take years to develop its data management technology. But just a year later, we're seeing the initial fruits of the company's labor manifested in Windows Server 2003.

Windows 2003 features an improved file system infrastructure; one of the key elements of this infrastructure is the Virtual Disk Service (VDS), which Microsoft designed to facilitate disk and data management. In conjunction with VDS, Microsoft provides in Windows 2003 three powerful tools for working with disks from a variety of vendors: the command-line tools diskraid.exe and diskpart.exe and the Microsoft Management Console (MMC) Disk Management snap-in.

VDS Architecture
Storage hardware vendors write a VDS hardware provider that translates general-purpose VDS APIs into specific instructions for their hardware. If you add a storage device that has a VDS hardware provider, Windows 2003 automatically installs and registers the storage device. In this way, Microsoft lets storage manufacturers enable their storage systems to be managed from within the Windows environment instead of through a proprietary management client.

Figure 1 shows the VDS architecture. Blue areas indicate storage hardware. Tan areas identify functionality built into Windows 2003, including the VDS abstraction layer and the Windows 2003 tools for working with VDS. Red sections represent storage vendor software in the form of client tools that integrate into Windows 2003 or hardware providers that tie storage devices to VDS. Note that Windows 2003 includes VDS software providers for both basic and dynamic disks. Basic providers include functionality for partitions and volumes. Dynamic providers include functionality for partitions and mirrored, striped, spanned, and RAID 5 volumes.

By providing a common interface into which storage manufacturers can plug their devices, Microsoft hopes to ease storage administration for Windows users. Manufacturers will probably continue to offer software management tools to exploit the unique capabilities of their hardware devices, but VDS might let storage administrators perform more tasks from one familiar interface, even if they manage different types of storage devices (e.g., RAID, Storage Area Network—SAN) from multiple vendors.

VDS is the foundation for the earlier mentioned DiskRaid and DiskPart command-line tools and the Disk Management snap-in. These three tools use VDS as a common architecture to access storage systems in Windows 2003. You'll find these tools more productive and powerful than previous Microsoft storage tools.

DiskRaid is a command-line tool that you can use to configure and manage RAID storage subsystems. DiskRaid is in the Microsoft Windows Server 2003 Deployment Kit and the Microsoft Windows Server 2003 Resource Kit; it isn't part of the OS. DiskRaid requires Windows 2003, and you must be a member of the Administrators group to use the tool.

DiskRaid works with any storage hardware that has a VDS hardware provider. Most storage manufacturers will supply VDS hardware providers with their newer storage systems. Older storage systems might not have VDS hardware providers. VDS must have registered at least one VDS hardware provider before you can use DiskRaid.

After you install DiskRaid, you can start it by typing


at a command prompt from the folder in which you installed the tool. Figure 2 shows this command and several other commands entered interactively. Table 1 lists all the DiskRaid commands. To get detailed help for any command, type the command followed by the /? option, for example:

list /?

DiskRaid's complete usage syntax is

diskraid \[/?| \[/s <filepath>\] \[/v\]

Table 2 describes DiskRaid's command-line options.

As the existence of the /s parameter suggests, DiskRaid is scriptable; however, it doesn't have Windows Script Host (WSH) support because its internals haven't been exposed to COM-compliant programming languages. The /s parameter lets DiskRaid process a text file of commands sequentially but doesn't support programmatic features such as iteration and If...Then...Else. The script that Listing 1 shows lists subsystems, providers, LUNs, and drives, then creates a LUN. The script that Web Listing 1 (, InstantDoc 39186) shows deletes a LUN.

After you use DiskRaid to create a LUN, Windows 2003 will be aware of it, so you can configure and manage it. Run the MMC Computer Management snap-in; under Storage, select Disk Management. The Initialize and Convert Disk Wizard will automatically run and will let you initialize and convert the newly created LUN. Alternatively, you can initialize and convert the LUN manually within Disk Management.

DiskPart is a command-line tool that lets you manage storage-system objects such as disks, partitions, and volumes. Microsoft ships the VDS implementation of DiskPart with Windows 2003, and it's installed automatically with the OS. DiskPart is also shipped with Windows XP, and you can download it for Windows 2000 from The Windows 2003 version of DiskPart has five new or enhanced commands (Automount, Repair, Inactive, GPT Attributes, and Remove). Like DiskRaid, the VDS implementation of DiskPart requires Windows 2003, and you must be a member of the Administrators group to use the tool.

DiskPart's command syntax is similar to DiskRaid's. The complete syntax is

diskpart \[/s <filepath>\] \[/?\]

As with DiskRaid, you can use DiskPart directly from a command prompt or with the /s option to run a script. You use the DiskPart tool directly by typing


at a command prompt from the folder in which you installed the tool. Figure 3 shows a DiskPart interactive session. Table 3 lists all the DiskPart commands. To get detailed help for any command, type the command followed by the /? option, for example:

convert /?

Like DiskRaid, DiskPart is scriptable—that is, it can process a text file of DiskPart commands sequentially—and its scripts have the same limitations as DiskRaid. The script in Listing 2 lists the available disks on a server, selects one, creates a volume on it, and assigns the volume a drive letter.

Almost everything you can do with DiskPart to configure and manage storage objects you can do with the Disk Management console, and vice versa. The difference, of course, is that DiskPart is a command-line tool and the Disk Management console has a GUI.

Disk Management
Disk Management is a VDS implementation of the Disk Management snap-in you might be familiar with from Win2K. The VDS Disk Management has no visible differences from the Win2K version. Disk Management is a system utility for managing hard disks and the volumes, or partitions, that they contain. Disk Management lets you initialize disks; create volumes; format volumes with the FAT, FAT32, or NTFS file system; and create fault-tolerant disk systems. With Disk Management, you can perform most disk-related tasks without restarting the system or interrupting users—most configuration changes take effect immediately.

To start Disk Management, click Start, All Programs, Administrative Tools, Computer Management. Under the Storage node, click Disk Management, as Figure 4 shows. You can, of course, add the Disk Management snap-in to any existing MMC console or create a new MMC console and add the Disk Management snap-in to the new console.

Disk Management features include:

  • A GUI. Right-click an object in the GUI to display the tasks you can perform on the selected object, and a wizard will guide you through creating a partition or volume or initializing and converting a disk.
  • Basic and dynamic disk configuration. Basic disks contain basic volumes, such as primary partitions and logical drives in extended partitions. Dynamic disks contain dynamic volumes that offer more features than basic disks, such as the ability to create fault-tolerant volumes on the Windows 2003 and Win2K systems. You can extend dynamic volumes (except system or boot volumes), mirror dynamic volumes, and add new dynamic disks without restarting the computer.
  • Local and remote disk management. You can manage any remote Windows 2003, Windows XP Professional Edition, or Win2K computer on which you're a member of the Backup Operators group or the Administrators group.
  • Drive mounting. You can mount a local drive on any empty folder on a local NTFS-formatted volume. Mounted drives make data more accessible and give you the flexibility to manage data storage based on your work environment and system usage. Mounted drives aren't subject to the 26-drive limit imposed by drive letters, so you can use mounted drives to access more than 26 drives on your computer.
  • MBR and GPT disk support. Disk Management offers support for Master Boot Record (MBR) disks in x86-based computers and support for MBR and globally unique identifier (GUID) partition table (GPT) disks in Itanium-based computers.
  • SAN support. When you add volumes to SANs, Windows 2003, Enterprise Edition and Windows 2003, Datacenter Edition don't automatically mount the volumes and assign them drive letters. Disk Management lets you perform these tasks manually. To use Disk Management to format the volume that the script in Listing 2 creates, you would right-click the Disk 2 volume labeled Drive E: and select Format, which opens the Format dialog box. Enter the volume name, choose the file system (e.g., NTFS), and click OK.

The combination of Windows 2003 VDS and the clients DiskRaid, DiskPart, and the Disk Management snap-in is a powerful storage management solution. Storage hardware manufacturers now have a standard interface that lets their storage devices automatically install and register themselves with Windows 2003. And administrators have one set of tools that they can use to configure and manage most storage system features, regardless of which vendor they purchase their systems from.

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