HP Data Protector 6.2 software integration with HP 3PAR Storage System

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VSS Writer
Each application or service that is running on Windows and wants to integrate with VSS framework
has to provide a VSS Writer specific for that application or service. The writer is responsible to
quiesce (pause) the application’s data and make it suitable for a make shadow copy/replica and
backup operation. At the same time, the application continues to be available to the user.
During restore, the writer ensures that the application is in the restore state and is not available to the
user (or at least the part affected by restore). In addition, writers make it possible for the
backup/recovery application to restore data back by unlocking files that are usually used by
application during normal operation. If necessary, writers also indicate alternate locations for data to
be restored.
For the list of writers that Data Protector supports, refer to the Data Protector VSS integration support
matrix listed in the For more information section.
Figure 1: Microsoft Volume Shadow Copy Service Overview
VSS Provider
VSS Provider is responsible for creating shadow copies/replicas when requested. The provider has to
maintain different instances of replicated volume without any reflection to the application’s I/O
operations. In addition, the provider has to support all replicas through its life cycle from creating,
manipulating, through to deleting.
There are three types of VSS providers:
• System provider that comes with Windows Operating System
• Software provider that can be provided by any third-party software vendor
• Hardware provider that is usually provided by disk-array vendors. It utilizes the disk array features
to create, maintain and delete replicas on the disk array itself. If replicas are created by hardware