HP Data Protector A.06.11 Integration Manual page 330

Data Protector supports the integration with VSS.
The Data Protector Volume Shadow Copy integration provides a unified
communication interface that can coordinate backup and restore of an application
regardless of their specific features. With this approach, a backup application does
not need to handle each application to be backed up specifically. However, the
production application as well as the backup application must conform to the VSS
specification.
Figure 99 on page 331 and Figure 100 on page 331 show the differences between
the traditional backup model and the model with the Data Protector Microsoft Volume
Shadow Copy integration.
330 Integrating the Data Protector ZDB integrations and Microsoft Volume Shadow Copy Service