User's Manual

2 Overview
This chapter provides an overview of supported components and system requirements for HP 3PAR
VSS Provider Software for Microsoft Windows.
Microsoft VSS
Microsoft includes VSS in the Windows 2003 and 2008 operating systems to simplify the
enterprise’s storage environment. VSS provides a framework for creating a point-in-time copy of
a single volume or multiple volumes.
Microsoft Windows Server 2003 and 2008 VSS work with VSS-aware applications to determine
when a volume shadow copy (snapshot) can be made. A snapshot is a copy of some data set, (a
disk volume for example), at a given point-in-time.
VSS Provider for Microsoft Windows-Aware Components
Microsoft provides a Software Development Kit (SDK) to enable independent hardware and software
vendors to interface with their components. This includes applications, data stores, snapshot engines,
and backup applications that interface with HP 3PAR VSS Provider Software for Microsoft Windows.
VSS Provider for Microsoft Windows was developed with VSS SDK, release 7.2 for Windows
2003 and Windows Server 2008 Platform SDK, as part of the VSS provider implementation.
To ensure absolute data integrity for all volumes, especially those that are interrelated, the
application, the backup program, and the backup device should be VSS aware, meaning that the
components participating in the backup must be specifically programmed to work with VSS Provider
for Microsoft Windows. These components are called writers, requestors, and providers, and are
described in detail in Table 1 (page 5).
Table 1 VSS Provider for Microsoft Windows Components
VSS Component DescriptionVSS Component
The requestor is backup software that initiates the creation of the shadow copy.Requestor
The writer is any application software that participates in the shadow copy
process and whose files and data are included in the process.
Writer
The provider is the storage technology that performs the actual shadow copy.Provider
Operation of VSS Provider for Microsoft Windows
VSS Provider for Microsoft Windows (Figure 1 (page 6)) communicates with the operating system
and applications, and temporarily freezes computing tasks to allow for the creation of and removal
of snapshots. The freeze function allows for the creation of a snapshot that reflects the state of
application data at a given point in time. When the process resumes, the original volume will
continue to change while the shadow copy of the volume remains constant.
VSS Provider for Microsoft Windows also gives permission for the backup application to access
the volume and back it up in its frozen state. The shadow copy volume is then used for the actual
backup. After the shadow copy volume is saved on the backup device, the shadow copy is deleted.
Microsoft VSS 5