HP V6.0 Software Microsoft Virtual Disk Service VDS, Microsoft Volume Shadow Copy Service VSS

HP Hardware Providers are not required in order for the Microsoft in-box or third party software providers to perform the tasks described above on the HP disk arrays. However, the HP HWPs extend the capabilities of various Windows providers and applications to do additional tasks that normally require the use of proprietary HP array management software. Such tasks include LUN and port management and more sophisticated volume copying.

Microsoft Virtual Disk Service (VDS)

Microsoft VDS provides a mechanism for managing volumes and logical units. Administrators can identify, configure, and monitor supported HP StorageWorks disk array volumes from the Windows Server 2003 Microsoft Management Console (MMC).

When used with HP disk arrays, VDS manages the array to make it appear like a Windows disk for Windows applications. When you use Microsoft Management Console, Windows Disk Manager and the Microsoft DiskPart or DiskRaid utility to control the array, your commands are sent to the array through VDS and the software or hardware providers.

VDS performs the following functions:

•Coordinates providers and clients (local and remote)

•Performs binding

•Discloses hardware LUNs to software disks

•Performs common file system functions

•Monitors volume status

•Provides fault and performance tracking

Microsoft Volume Shadow Copy Service (VSS)

Microsoft’s VSS manages creation and maintenance of data shadow copies for backup and recovery, including copies across multiple volumes. To accomplish this, VSS coordinates with HP’s Fast Recovery Solution and Business Copy software or other third party business applications, file-system services, backup applications, and the storage hardware.

The shadow copies contain static copies of all files, such as databases, transaction logs, and checkpoint files. Because VSS coordinates copying, the files are copied in a defined state.

Copy terminology

Understanding how Microsoft VSS terminology corresponds to standard IT industry terms for data copying makes it easier to understand what VSS does. The following paragraphs explain the terminology.

Microsoft generally refers to a VSS copy as a “volume shadow copy.” When created using HP FRS and HWP, this type of copy is a static replica of an original volume’s contents. It is keyed with a GUID to allow identification of the parts of a shadow copy set that span multiple volumes. Microsoft also refers to a VSS copy as a “plex.” This type of copy is commonly referred to in the IT industry as a “split mirror.”

When you use an EVA array to make a shadow copy, the array makes what is known as a “snapclone.” An EVA Snapclone is a complete clone copy of a specified Virtual Disk (LUN). EVA snapclones are available almost immediately. This is accomplished by creating a point-in-time copy and making it immediately available by pointing to data on the original volume while continuing to copy data to a secondary volume in the background. When copying is complete, the snapclone is a static point-in-time copy of the original.

HP VDS/VSS Hardware Providers

Windows Server 2003 sees, partitions, mounts, and manages file systems on the disk array using its own software providers. HP’s Hardware Providers extend the array management capabilities of Windows and its applications to include functions normally performed using the disk array’s proprietary control software. These functions include managing disk array LUNs and ports and performing volume copy operations.

14 Overview