VDS_DISK_EXTENT structure (vds.h)

[Beginning with Windows 8 and Windows Server 2012, the Virtual Disk Service COM interface is superseded by the Windows Storage Management API.]

Defines the properties of a disk extent.

Syntax

typedef struct _VDS_DISK_EXTENT {
  VDS_OBJECT_ID        diskId;
  VDS_DISK_EXTENT_TYPE type;
  ULONGLONG            ullOffset;
  ULONGLONG            ullSize;
  VDS_OBJECT_ID        volumeId;
  VDS_OBJECT_ID        plexId;
  ULONG                memberIdx;
} VDS_DISK_EXTENT, *PVDS_DISK_EXTENT;

Members

diskId

The GUID of the disk.

type

A VDS_DISK_EXTENT_TYPE enumeration value that specifies the type of the disk extent.

ullOffset

The disk offset, in bytes.

ullSize

The size of the extent, in bytes.

volumeId

The GUID of the volume to which the extent belongs.

plexId

If the extent is from a volume, this member is the GUID of the plex to which the extent belongs.

memberIdx

If the extent is from a volume plex, this member is the zero-based index of the plex member to which the extent belongs.

Remarks

The volumeId, plexId, and memberIdx members apply to data and ESP partitions only. If the extent lacks a volume association, the GUIDs for volumeId and plexId are GUID_NULL, and memberIdx is zero. The memberIdx member is always zero unless the volume is striped or striped with parity (RAID-5). An extent can also be unallocated or free.

The IVdsDisk::QueryExtents method returns this structure to report the property details of a disk extent. Likewise, the IVdsVolumePlex::QueryExtents method returns it to report the details of the disk extents allocated to a plex.

A disk extent is a contiguous set of blocks on a single disk or LUN handled by a software provider. A drive extent is not required to be a contiguous set of blocks.

Requirements

See also

Disk Object

IVdsDisk::QueryExtents

IVdsVolumePlex::QueryExtents

VDS Structures

VDS_DISK_EXTENT_TYPE