Msvm_StorageAllocationSettingData class

Article
01/07/2021

Represents settings specifically related to the allocation of virtual storage.

The following syntax is simplified Managed Object Format (MOF) code, and it includes all of the inherited properties.

Syntax

[Dynamic, Provider("VmmsWmiInstanceAndMethodProvider"), AMENDMENT]
class Msvm_StorageAllocationSettingData : CIM_StorageAllocationSettingData
{
  string  InstanceID;
  string  Caption = "Hard Disk Image Default Settings";
  string  Description = "Describes the default settings for the hard disk image resources";
  string  ElementName;
  uint16  ResourceType;
  string  OtherResourceType;
  string  ResourceSubType;
  string  PoolID;
  uint16  ConsumerVisibility;
  string  HostResource[];
  string  AllocationUnits;
  uint64  VirtualQuantity;
  uint64  Limit = 1;
  uint32  Weight;
  string  StorageQoSPolicyID;
  boolean AutomaticAllocation;
  boolean AutomaticDeallocation;
  string  Parent;
  string  Connection[];
  string  Address;
  uint16  MappingBehavior;
  string  AddressOnParent;
  uint64  VirtualResourceBlockSize;
  string  VirtualQuantityUnits = "count(fixed size block)";
  uint16  Access;
  uint64  HostResourceBlockSize;
  uint64  Reservation;
  uint64  HostExtentStartingAddress;
  string  HostExtentName;
  uint16  HostExtentNameFormat;
  string  OtherHostExtentNameFormat;
  uint16  HostExtentNameNamespace;
  string  OtherHostExtentNameNamespace;
  uint64  IOPSLimit;
  uint64  IOPSReservation;
  string  IOPSAllocationUnits;
  boolean PersistentReservationsSupported;
  uint16  CachingMode;
  string  SnapshotId = "";
  boolean IgnoreFlushes;
  uint16  WriteHardeningMethod;
};

Members

The Msvm_StorageAllocationSettingData class has these types of members:

Properties

Properties

The Msvm_StorageAllocationSettingData class has these properties.

Access

Data type: uint16
Access type: Read-only

Specifies the storage access. This property is inherited from CIM_StorageAllocationSettingData.

Unknown (0)
Readable (1)
Writeable (2)
Read/Write Supported (3)

Address

Data type: string
Access type: Read-only

The address of the resource. This property is inherited from CIM_ResourceAllocationSettingData.

AddressOnParent

Data type: string
Access type: Read-only

Describes the address of this resource in the context of the parent. The Parent and AddressOnParent properties are used to describe the controller relationship as well as the ordering of devices on a controller. This property is inherited from CIM_ResourceAllocationSettingData.

AllocationUnits

Data type: string
Access type: Read-only

The units of allocation used by the Reservation and Limit properties. This property is inherited from CIM_ResourceAllocationSettingData.

AutomaticAllocation

Data type: boolean
Access type: Read-only

Indicates whether the resource will be automatically allocated. This property is inherited from CIM_ResourceAllocationSettingData.

AutomaticDeallocation

Data type: boolean
Access type: Read-only

Indicates whether the resource will be automatically deallocated. This property is inherited from CIM_ResourceAllocationSettingData.

CachingMode

Data type: uint16
Access type: Read-only

Indicates whether and how in-memory file caching should be used for this VHD. The default policy is set in the DefaultVirtualHardDiskCachingMode field of the Msvm_VirtualSystemManagementServiceSettingData class.

Note

Added in Windows 10.

Unknown (0)

Default (2)

No Caching (3)

Cache Sharable Parents (4)

Caption

Data type: string
Access type: Read-only
Qualifiers: MaxLen (64)

A short description of the object. This property is inherited from CIM_ManagedElement, and it is always set to "Hard Disk Image Default Settings".

Connection

Data type: string array
Access type: Read-only

The device to which this resource is connected. This property is inherited from CIM_ResourceAllocationSettingData.

ConsumerVisibility

Data type: uint16
Access type: Read-only

The consumer's visibility to the allocated resource. This property is inherited from CIM_ResourceAllocationSettingData.

Unknown (0)
Passed-Through (2)
Virtualized (3)
Not represented (4)

Description

Data type: string
Access type: Read-only

A description of the object. This property is inherited from CIM_ManagedElement, and it is always set to "Describes the default settings for the hard disk image resources".

ElementName

Data type: string
Access type: Read-only

A display name for the object. This property is inherited from CIM_SettingData.

HostExtentName

Data type: string
Access type: Read-only

A unique identifier for the host extent. The identified host extent is used for the storage resource allocation. This property is inherited from CIM_StorageAllocationSettingData.

HostExtentNameFormat

Data type: uint16
Access type: Read-only

Identifies the format that is used for the HostExtentName property. This property is inherited from CIM_StorageAllocationSettingData.

Unknown (0)
Other (1)
SNVM (7)
NAA (9)
EUI64 (10)
T10VID (11)
OS Device Name (12)
DMTF Reserved (.. )

HostExtentNameNamespace

Data type: uint16
Access type: Read-only

If the host extent is a SCSI volume, then the preferred source for SCSI volume names is SCSI VPD Page 83 responses. This property is inherited from CIM_StorageAllocationSettingData.

Unknown (0)
Other (1)
VPD83Type3 (2)
VPD83Type2 (3)
VPD83Type1 (4)
VPD80 (5)
NodeWWN (6)
SNVM (7)
OS Device Namespace (8)
DMTF Reserved (.. )

HostExtentStartingAddress

Data type: uint64
Access type: Read-only

Identifies the starting address on the host storage extent, identified by the HostExtentName property, that is used for the allocation of the virtual storage extent. A Null value indicates that there is no direct mapping of the virtual storage extent to the referenced host storage extent. This property is inherited from CIM_StorageAllocationSettingData.

HostResource

Data type: string array
Access type: Read-only

Only one host resource can be assigned to each device in the virtual machine, so only the first element of this array can be set. For devices that support this feature, set the first element of the HostResource array to contain a reference to the underlying host resource to be assigned. This property is inherited from CIM_ResourceAllocationSettingData.

This is a read-only property. But if the ResourceType property is 31 (Logical Disk) and the ResourceSubType property is "Microsoft:Hyper-V:Virtual Hard Disk", "Microsoft:Hyper-V:Virtual CD/DVD Disk", or "Microsoft:Hyper-V:Virtual Floppy Disk", the HostResource property can be changed by using the ModifyResourceSettings method of the Msvm_VirtualSystemManagementService class.

HostResourceBlockSize

Data type: uint64
Access type: Read-only

The size, in bytes, of the blocks that are allocated at the host as the result of this storage resource allocation or storage resource allocation request. If the block size is variable, then the maximum block size, in bytes, will be specified. If the block size is unknown or if a block concept does not apply, then the value 1 will be used. This property is inherited from CIM_StorageAllocationSettingData.

IgnoreFlushes

Data type: boolean
Access type: Read-only

If set to true, Hyper-V will ignore write back flushing for that particular virtual machine. If set to false, Hyper-V will continue to write back to the disk on every flush. The default setting is false.

Windows 10: This value is not supported until Windows 10.

InstanceID

Data type: string
Access type: Read-only
Qualifiers: Key

Uniquely identifies an instance of this class. This property is inherited from CIM_SettingData.

IOPSAllocationUnits

Data type: string
Access type: Read-only

Specifies the allocation units used by the IOPSLimit and IOPSReservation properties. This property always has the value:

"count(normalized I/O) / second"

Throughput is measured in normalized I/O operations per second (IOPS) instead of raw IOPS. When using normalized IOPS, each I/O request is accounted for as 1 normalized I/O if the size of the request is less than or equal to a predefined base size (8 KB). Requests that are larger than the base size are accounted for as N I/O operations, where N is the rounded-up value of the request size divided by the base size. For example, if the base size is 8 KB, a 16-KB request is counted as 2 normalized I/O operations, a 32-KB request as 4 normalized I/O operations, and so on.

Windows 8.1: This value is not supported until Windows 8.1 and Windows Server 2012 R2.

IOPSLimit

Data type: uint64
Access type: Read-only
Qualifiers: MaxValue (1000000000)

The maximum number of I/O operations per second (IOPS) that will be serviced for this virtual storage extent. If the value isn't defined or is zero, there is no limit to the number of IOPS that the device can issue.

Note

You can use the ModifyResourceSettings method of the Msvm_VirtualSystemManagementService class to modify the value of this property. This property is meaningful only for Msvm_StorageAllocationSettingData instances that request resource allocations for virtual machines. It's ignored when allocating resources to a child pool.

Windows 8.1: This value is not supported until Windows 8.1 and Windows Server 2012 R2.

IOPSReservation

Data type: uint64
Access type: Read-only
Qualifiers: MaxValue (1000000000)

The minimum number of I/O operations per second (IOPS) that will be serviced for this virtual storage extent.

If both IOPSLimit and IOPSReservation are defined, the value of IOPSLimit must be greater than or equal to the value of IOPSReservation.

Note

Windows 8.1: This value is not supported until Windows 8.1 and Windows Server 2012 R2.

Limit

Data type: uint64
Access type: Read-only

The maximum number of blocks that will be granted for this storage resource allocation at the host. The block size is specified by the HostResourceBlockSize property. Usually the value of this property would reflect a maximum size for the allocated host extent that matches the size of the virtual storage extent presented to the consumer. A value less than that would indicate a situation where a sparsely populated virtual storage extent is expected, where the fill rate is limited by the value of the Limit property. This property is inherited from CIM_ResourceAllocationSettingData.

MappingBehavior

Data type: uint16
Access type: Read-only

Specifies how this resource maps to underlying resources. This property is inherited from CIM_ResourceAllocationSettingData.

OtherHostExtentNameFormat

Data type: string
Access type: Read-only

A string that describes the format of the HostExtentName property if the HostExtentNameFormat property is 1 (Other). This property is inherited from CIM_StorageAllocationSettingData.

OtherHostExtentNameNamespace

Data type: string
Access type: Read-only

A string that describes the namespace of the HostExtentName property if the HostExtentNameNamespace property contains 1 (Other). This property is inherited from CIM_StorageAllocationSettingData.

OtherResourceType

Data type: string
Access type: Read-only

A string that describes the resource type when a well-defined value is not available and ResourceType has the value 1(Other). This property is inherited from CIM_ResourceAllocationSettingData.

Parent

Data type: string
Access type: Read-only

The parent of the resource. This property is inherited from CIM_ResourceAllocationSettingData.

PersistentReservationsSupported

Data type: boolean
Access type: Read-only

Indicates whether the virtual hard disk supports SCSI-3 persistent reservations.

Windows 8.1: This value is not supported until Windows 8.1 and Windows Server 2012 R2.

PoolID

Data type: string
Access type: Read-only

The identifier of the resource pool from which this resource was allocated. This property is inherited from CIM_ResourceAllocationSettingData.

Reservation

Data type: uint64
Access type: Read-only
Qualifiers: Override ("Reservation"), ModelCorrespondence ("CIM_StorageAllocationSettingData.HostResourceBlockSize")

The number of blocks that are guaranteed to be available for this storage resource allocation at the host. The block size is specified by the HostResourceBlockSize property. This property is inherited from CIM_StorageAllocationSettingData.

ResourceSubType

Data type: string
Access type: Read-only

A string that describes an implementation-specific subtype for this resource. For example, this may be used to distinguish different models of the same resource type. This property is inherited from CIM_ResourceAllocationSettingData.

ResourceType

Data type: uint16
Access type: Read-only

The type of resource this allocation setting represents. This property is inherited from CIM_ResourceAllocationSettingData.

Other (1)
Computer System (2)
Processor (3)
Memory (4)
IDE Controller (5)
Parallel SCSI HBA (6)
FC HBA (7)
iSCSI HBA (8)
IB HCA (9)
Ethernet Adapter (10)
Other Network Adapter (11)
I/O Slot (12)
I/O Device (13)
Diskette Drive (14)
CD Drive (15)
DVD drive (16)
Disk Drive (17)
Tape Drive (18)
Storage Extent (19)
Other Storage Device (20)
Serial port (21)
Parallel port (22)
USB controller (23)
Graphics controller (24)
IEEE 1394 controller (25)
Partitionable Unit (26)
Base Partitionable Unit (27)
Power Supply (28)
Cooling Device (29)
Ethernet Switch Port (30)
Logical Disk (31)
Storage Volume (32)
Ethernet connection (33)
DMTF reserved (30 32767)
Vendor Reserved (32768 65535)

SnapshotId

Data type: string
Access type: Read-only

A GUID representing which snapshot within the VHD Set file is to be attached.

Note

Added in Windows 10.

StorageQoSPolicyID

Data type: string
Access type: Read-only

Specifies the unique identifier of the Storage QoS Policy to be applied to this virtual storage extent.

Note

Added in Windows 10.

VirtualQuantity

Data type: uint64
Access type: Read-only

The number of blocks that are presented to the consumer. The block size is specified by the VirtualResourceBlockSize property. This property is inherited from CIM_ResourceAllocationSettingData.

VirtualQuantityUnits

Data type: string
Access type: Read-only

Specifies the units used by the VirtualQuantity property. This property is inherited from CIM_StorageAllocationSettingData.

Value	Meaning
"count(fixed size block)"	The fixed block size is contained in the VirtualResourceBlockSize property.
"byte"	The VirtualQuantity property is measured in bytes.

VirtualResourceBlockSize

Data type: uint64
Access type: Read-only

The size, in bytes, of the blocks that are presented to the consumer as the result of this storage resource allocation or storage resource allocation request. If the block size is variable, then the maximum block size, in bytes, will be specified. If the block size is unknown or if a block concept does not apply, then the value 1 will be used. This property is inherited from CIM_StorageAllocationSettingData.

Weight

Data type: uint32
Access type: Read-only
Qualifiers: Override ("Weight"), MinValue (1), MaxValue (10000)

Specifies a relative priority for this allocation in relation to other allocations from the same resource pool. This property has no unit of measure and is only relevant when compared to other allocations vying for the same host resources. This property is inherited from CIM_ResourceAllocationSettingData.

Range: 1 10000

WriteHardeningMethod

Data type: uint16
Access type: Read-only

Indicates what write hardening method is supported by the disk.

Note

This property was added in Windows 10, version 1703.

Default (0)

WriteCacheEnabled (1)

WriteCacheandFUAEnabled (2)

WriteCacheDisabled (3)

Requirements

Requirement	Value
Minimum supported client	Windows 8 [desktop apps only]
Minimum supported server	Windows Server 2012 [desktop apps only]
Namespace	Root\Virtualization\V2
MOF	WindowsVirtualization.V2.mof
DLL	Vmms.exe

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Msvm_StorageAllocationSettingData class

Syntax

Members

Properties

Requirements

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