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VssSnapshotContext Enumeration

The VssSnapshotContext enumeration enables a requester using SetContext Overload to specify how a shadow copy is to be created, queried, or deleted and the degree of writer involvement. IVssBackupComponents::SetContext" method) may be modified by a bitmask that contains a valid combination of VssVolumeSnapshotAttributes and VssSnapshotContext enumeration values.

Namespace:  Alphaleonis.Win32.Vss
Assembly:  AlphaVSS.Common (in AlphaVSS.Common.dll) Version: 1.4.0.0 (1.4.0.0)
Syntax
public enum VssSnapshotContext
Members
  Member nameValueDescription
Backup0 The standard backup context. Specifies an auto-release, nonpersistent shadow copy in which writers are involved in the creation.
FileShareBackup16 Specifies a nonpersistent and auto-release shadow copy created without writer involvement.
NasRollback25

Specifies a persistent and non-auto-release shadow copy without writer involvement. This context should be used when there is no need for writer involvement to ensure that files are in a consistent state at the time of the shadow copy.

Lightweight automated file rollback mechanisms or persistent shadow copies of file shares or data volumes that are not expected to contain any system-related files or databases might run under this context. For example, a requester could use this context for creating a shadow copy of a NAS volume hosting documents and simple user shares. Those types of data do not need writer involvement to create a consistent shadow copy.

AppRollback9

Specifies a persistent and non-auto-release shadow copy with writer involvement. This context is designed to be used when writers are needed to ensure that files are in a well-defined state prior to shadow copy.

Automated file rollback mechanisms of system volumes and shadow copies to be used in data mining or restore operations might run under this context. This context is similar to VSS_CTX_BACKUP but allows a requester more control over the persistence of the shadow copy.

ClientAccessible29

Specifies a read-only, client-accessible shadow copy supporting Shadow Copies for Shared Folders and created without writer involvement. Only the system provider (the default provider available on the system) can create this type of shadow copy.

Most requesters will want to use the NasRollback context for persistent, non-auto-release shadow copies without writer involvement.

ClientAccessibleWriters13

Specifies a read-only, client-accessible shadow copy supporting Shadow Copies for Shared Folders and created with writer involvement. Only the system provider (the default provider available on the system) can create this type of shadow copy.

Most requesters will want to use the AppRollback context for persistent, non-auto-release shadow copies with writer involvement.

Windows Server 2003 and Windows XP: This context is not supported by Windows Server 2003 and Windows XP.

All4294967295 All types of currently live shadow copies are available for administrative operations, such as shadow copy queries (see the Query method in IVssBackupComponents). All is a valid context for all VSS interfaces except IVssBackupComponents::StartSnapshotSet and IVssBackupComponents::DoSnapshotSet.
Remarks
VssSnapshotContext is defined as a static class defining the base VssVolumeSnapshotAttributes combination of values representing the VSS_CTX_XXXXXX constants defined in the VSS API.
See Also