DSCResources/DSC_Disk/DSC_Disk.psm1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
$modulePath = Join-Path -Path (Split-Path -Path (Split-Path -Path $PSScriptRoot -Parent) -Parent) -ChildPath 'Modules'

# Import the Storage Common Module.
Import-Module -Name (Join-Path -Path $modulePath `
        -ChildPath (Join-Path -Path 'StorageDsc.Common' `
            -ChildPath 'StorageDsc.Common.psm1'))

Import-Module -Name (Join-Path -Path $modulePath -ChildPath 'DscResource.Common')

# Import Localization Strings.
$script:localizedData = Get-LocalizedData -DefaultUICulture 'en-US'

<#
    .SYNOPSIS
        Returns the current state of the Disk and Partition.
 
    .PARAMETER DriveLetter
        Specifies the preferred letter to assign to the disk volume.
 
    .PARAMETER DiskId
        Specifies the disk identifier for the disk to modify.
 
    .PARAMETER DiskIdType
        Specifies the identifier type the DiskId contains. Defaults to Number.
 
    .PARAMETER PartitionStyle
        Specifies the partition style of the disk. Defaults to GPT.
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER Size
        Specifies the size of new volume (use all available space on disk if not provided).
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER FSLabel
        Specifies the volume label to assign to the volume.
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER AllocationUnitSize
        Specifies the allocation unit size to use when formatting the volume.
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER FSFormat
        Specifies the file system format of the new volume.
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER AllowDestructive
        Specifies if potentially destructive operations may occur.
        This parameter is not used in Get-TargetResource.
 
    .PARAMETER ClearDisk
        Specifies if the disks partition schema should be removed entirely, even if data and OEM
        partitions are present. Only possible with AllowDestructive enabled.
        This parameter is not used in Get-TargetResource.
#>

function Get-TargetResource
{
    [CmdletBinding()]
    [OutputType([System.Collections.Hashtable])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $DriveLetter,

        [Parameter(Mandatory = $true)]
        [System.String]
        $DiskId,

        [Parameter()]
        [ValidateSet('Number', 'UniqueId', 'Guid', 'Location')]
        [System.String]
        $DiskIdType = 'Number',

        [Parameter()]
        [ValidateSet('GPT', 'MBR')]
        [System.String]
        $PartitionStyle = 'GPT',

        [Parameter()]
        [System.UInt64]
        $Size,

        [Parameter()]
        [System.String]
        $FSLabel,

        [Parameter()]
        [System.UInt32]
        $AllocationUnitSize,

        [Parameter()]
        [ValidateSet('NTFS', 'ReFS')]
        [System.String]
        $FSFormat = 'NTFS',

        [Parameter()]
        [System.Boolean]
        $AllowDestructive,

        [Parameter()]
        [System.Boolean]
        $ClearDisk
    )

    Write-Verbose -Message ( @(
            "$($MyInvocation.MyCommand): "
            $($script:localizedData.GettingDiskMessage -f $DiskIdType, $DiskId, $DriveLetter)
        ) -join '' )

    # Validate the DriveLetter parameter
    $DriveLetter = Assert-DriveLetterValid -DriveLetter $DriveLetter

    # Get the Disk using the identifiers supplied
    $disk = Get-DiskByIdentifier `
        -DiskId $DiskId `
        -DiskIdType $DiskIdType

    $partition = Get-Partition `
        -DriveLetter $DriveLetter `
        -ErrorAction SilentlyContinue | Select-Object -First 1

    $volume = Get-Volume `
        -DriveLetter $DriveLetter `
        -ErrorAction SilentlyContinue

    $blockSize = (Get-CimInstance `
            -Query "SELECT BlockSize from Win32_Volume WHERE DriveLetter = '$($DriveLetter):'" `
            -ErrorAction SilentlyContinue).BlockSize

    return @{
        DiskId             = $DiskId
        DiskIdType         = $DiskIdType
        DriveLetter        = $partition.DriveLetter
        PartitionStyle     = $disk.PartitionStyle
        Size               = $partition.Size
        FSLabel            = $volume.FileSystemLabel
        AllocationUnitSize = $blockSize
        FSFormat           = $volume.FileSystem
    }
} # Get-TargetResource

<#
    .SYNOPSIS
        Initializes the Disk and Partition and assigns the drive letter.
 
    .PARAMETER DriveLetter
        Specifies the preferred letter to assign to the disk volume.
 
    .PARAMETER DiskId
        Specifies the disk identifier for the disk to modify.
 
    .PARAMETER DiskIdType
        Specifies the identifier type the DiskId contains. Defaults to Number.
 
    .PARAMETER PartitionStyle
        Specifies the partition style of the disk. Defaults to GPT.
 
    .PARAMETER Size
        Specifies the size of new volume. Leave empty to use the remaining free space.
 
    .PARAMETER FSLabel
        Specifies the volume label to assign to the volume.
 
    .PARAMETER AllocationUnitSize
        Specifies the allocation unit size to use when formatting the volume.
 
    .PARAMETER FSFormat
        Specifies the file system format of the new volume.
 
    .PARAMETER AllowDestructive
        Specifies if potentially destructive operations may occur.
 
    .PARAMETER ClearDisk
        Specifies if the disks partition schema should be removed entirely, even if data and OEM
        partitions are present. Only possible with AllowDestructive enabled.
#>

function Set-TargetResource
{
    # Should process is called in a helper functions but not directly in Set-TargetResource
    [Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSShouldProcess', '')]
    [CmdletBinding(SupportsShouldProcess = $true)]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $DriveLetter,

        [Parameter(Mandatory = $true)]
        [System.String]
        $DiskId,

        [Parameter()]
        [ValidateSet('Number', 'UniqueId', 'Guid', 'Location')]
        [System.String]
        $DiskIdType = 'Number',

        [Parameter()]
        [ValidateSet('GPT', 'MBR')]
        [System.String]
        $PartitionStyle = 'GPT',

        [Parameter()]
        [System.UInt64]
        $Size,

        [Parameter()]
        [System.String]
        $FSLabel,

        [Parameter()]
        [System.UInt32]
        $AllocationUnitSize,

        [Parameter()]
        [ValidateSet('NTFS', 'ReFS')]
        [System.String]
        $FSFormat = 'NTFS',

        [Parameter()]
        [System.Boolean]
        $AllowDestructive,

        [Parameter()]
        [System.Boolean]
        $ClearDisk
    )

    Write-Verbose -Message ( @(
            "$($MyInvocation.MyCommand): "
            $($script:localizedData.SettingDiskMessage -f $DiskIdType, $DiskId, $DriveLetter)
        ) -join '' )

    # Validate the DriveLetter parameter
    $DriveLetter = Assert-DriveLetterValid -DriveLetter $DriveLetter

    # Get the Disk using the identifiers supplied
    $disk = Get-DiskByIdentifier `
        -DiskId $DiskId `
        -DiskIdType $DiskIdType

    if ($disk.IsOffline)
    {
        # Disk is offline, so bring it online
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.SetDiskOnlineMessage -f $DiskIdType, $DiskId)
            ) -join '' )

        $disk | Set-Disk -IsOffline $false
    } # if

    if ($disk.IsReadOnly)
    {
        # Disk is read-only, so make it read/write
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.SetDiskReadWriteMessage -f $DiskIdType, $DiskId)
            ) -join '' )

        $disk | Set-Disk -IsReadOnly $false
    } # if

    Write-Verbose -Message ( @(
            "$($MyInvocation.MyCommand): "
            $($script:localizedData.CheckingDiskPartitionStyleMessage -f $DiskIdType, $DiskId)
        ) -join '' )

    if ($AllowDestructive -and $ClearDisk -and $disk.PartitionStyle -ne 'RAW')
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.ClearingDiskMessage -f $DiskIdType, $DiskId)
            ) -join '' )

        $disk | Clear-Disk -RemoveData -RemoveOEM -Confirm:$true

        # Requery the disk
        $disk = Get-DiskByIdentifier `
            -DiskId $DiskId `
            -DiskIdType $DiskIdType
    }

    if ($disk.PartitionStyle -eq 'RAW')
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.InitializingDiskMessage -f $DiskIdType, $DiskId, $PartitionStyle)
            ) -join '' )

        $disk | Initialize-Disk -PartitionStyle $PartitionStyle
    }
    else
    {
        if ($disk.PartitionStyle -eq $PartitionStyle)
        {
            # The disk partition is already initialized with the correct partition style
            Write-Verbose -Message ( @(
                    "$($MyInvocation.MyCommand): "
                    $($script:localizedData.DiskAlreadyInitializedMessage `
                            -f $DiskIdType, $DiskId, $disk.PartitionStyle)
                ) -join '' )

        }
        else
        {
            # This disk is initialized but with the incorrect partition style
            New-InvalidOperationException `
                -Message ($script:localizedData.DiskInitializedWithWrongPartitionStyleError `
                    -f $DiskIdType, $DiskId, $disk.PartitionStyle, $PartitionStyle)
        }
    }

    # Get the partitions on the disk
    $partition = $disk | Get-Partition -ErrorAction SilentlyContinue

    # Check if the disk has an existing partition assigned to the drive letter
    $assignedPartition = $partition |
        Where-Object -Property DriveLetter -eq $DriveLetter

    # Check if existing partition already has file system on it
    if ($null -eq $assignedPartition)
    {
        # There is no partiton with this drive letter
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DriveNotFoundOnPartitionMessage `
                        -f $DiskIdType, $DiskId, $DriveLetter)
            ) -join '' )

        # Are there any partitions defined on this disk?
        if ($partition)
        {
            # There are partitions defined - identify if one matches the size required
            if ($Size)
            {
                # Find the first basic partition matching the size
                $partition = $partition |
                    Where-Object -FilterScript { $_.Type -eq 'Basic' -and $_.Size -eq $Size } |
                    Select-Object -First 1

                if ($partition)
                {
                    # A partition matching the required size was found
                    Write-Verbose -Message ($script:localizedData.MatchingPartitionFoundMessage `
                            -f $DiskIdType, $DiskId, $partition.PartitionNumber)
                }
                else
                {
                    # A partition matching the required size was not found
                    Write-Verbose -Message ($script:localizedData.MatchingPartitionNotFoundMessage `
                            -f $DiskIdType, $DiskId)
                } # if
            }
            else
            {
                <#
                    No size specified, so see if there is a partition that has a volume
                    matching the file system type that is not assigned to a drive letter.
                #>

                Write-Verbose -Message ($script:localizedData.MatchingPartitionNoSizeMessage `
                        -f $DiskIdType, $DiskId)

                $searchPartitions = $partition | Where-Object -FilterScript {
                    $_.Type -eq 'Basic' -and -not [System.Char]::IsLetter($_.DriveLetter)
                }

                $partition = $null

                foreach ($searchPartition in $searchPartitions)
                {
                    # Look for the volume in the partition.
                    Write-Verbose -Message ($script:localizedData.SearchForVolumeMessage `
                            -f $DiskIdType, $DiskId, $searchPartition.PartitionNumber, $FSFormat)

                    $searchVolumes = $searchPartition | Get-Volume

                    $volumeMatch = $searchVolumes | Where-Object -FilterScript {
                        $_.FileSystem -eq $FSFormat
                    }

                    if ($volumeMatch)
                    {
                        <#
                            Found a partition with a volume that matches file system
                            type and not assigned a drive letter.
                        #>

                        $partition = $searchPartition

                        Write-Verbose -Message ($script:localizedData.VolumeFoundMessage `
                                -f $DiskIdType, $DiskId, $searchPartition.PartitionNumber, $FSFormat)

                        break
                    } # if
                } # foreach
            } # if
        } # if

        # Do we need to create a new partition?
        if (-not $partition)
        {
            # Attempt to create a new partition
            $partitionParams = @{
                DriveLetter = $DriveLetter
            }

            if ($Size)
            {
                # Use only a specific size
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.CreatingPartitionMessage `
                                -f $DiskIdType, $DiskId, $DriveLetter, "$($Size/1KB) KB")
                    ) -join '' )

                $partitionParams['Size'] = $Size
            }
            else
            {
                # Use the entire disk
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.CreatingPartitionMessage `
                                -f $DiskIdType, $DiskId, $DriveLetter, 'all free space')
                    ) -join '' )

                $partitionParams['UseMaximumSize'] = $true
            } # if

            # Create the partition.
            $partition = $disk | New-Partition @partitionParams

            <#
                After creating the partition it can take a few seconds for it to become writeable
                Wait for up to 30 seconds for the parition to become writeable
            #>

            $timeAtStart = Get-Date
            $minimumTimeToWait = $timeAtStart + (New-Timespan -Second 3)
            $maximumTimeToWait = $timeAtStart + (New-Timespan -Second 30)

            while (($partitionstate.IsReadOnly -and (Get-Date) -lt $maximumTimeToWait) `
                -or ((Get-Date) -lt $minimumTimeToWait))
            {
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        ($script:localizedData.NewPartitionIsReadOnlyMessage `
                                -f $DiskIdType, $DiskId, $partition.PartitionNumber)
                    ) -join '' )

                Start-Sleep -Seconds 1

                # Pull the partition details again to check if it is readonly
                $partitionstate = $partition | Get-Partition
            } # while
        } # if

        if ($partition.IsReadOnly)
        {
            # The partition is still readonly - throw an exception
            New-InvalidOperationException `
                -Message ($script:localizedData.NewParitionIsReadOnlyError `
                    -f $DiskIdType, $DiskId, $partition.PartitionNumber)
        } # if

        $assignDriveLetter = $true
    }
    else
    {
        # The disk already has a partition on it that is assigned to the Drive Letter
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.PartitionAlreadyAssignedMessage `
                        -f $DriveLetter, $assignedPartition.PartitionNumber)
            ) -join '' )

        $assignDriveLetter = $false

        $supportedSize = $assignedPartition | Get-PartitionSupportedSize

        <#
            If the parition size was not specified then try and make the partition
            use all possible space on the disk.
        #>

        if (-not ($PSBoundParameters.ContainsKey('Size')))
        {
            $Size = $supportedSize.SizeMax
        }

        if ($assignedPartition.Size -ne $Size)
        {
            # A patition resize is required
            if ($AllowDestructive)
            {
                if ($FSFormat -eq 'ReFS')
                {
                    Write-Warning -Message ( @(
                            "$($MyInvocation.MyCommand): "
                            $($script:localizedData.ResizeRefsNotPossibleMessage `
                                    -f $DriveLetter, $assignedPartition.Size, $Size)
                        ) -join '' )

                }
                else
                {
                    Write-Verbose -Message ( @(
                            "$($MyInvocation.MyCommand): "
                            $($script:localizedData.SizeMismatchCorrectionMessage `
                                    -f $DriveLetter, $assignedPartition.Size, $Size)
                        ) -join '' )

                    if ($Size -gt $supportedSize.SizeMax)
                    {
                        New-InvalidArgumentException -Message ( @(
                                "$($MyInvocation.MyCommand): "
                                $($script:localizedData.FreeSpaceViolationError `
                                        -f $DriveLetter, $assignedPartition.Size, $Size, $supportedSize.SizeMax)
                            ) -join '' ) -ArgumentName 'Size' -ErrorAction Stop
                    }

                    $assignedPartition | Resize-Partition -Size $Size
                }
            }
            else
            {
                # A partition resize was required but is not allowed
                Write-Warning -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.ResizeNotAllowedMessage `
                                -f $DriveLetter, $assignedPartition.Size, $Size)
                    ) -join '' )
            }
        }
    }

    # Get the Volume on the partition
    $volume = $partition | Get-Volume

    # Is the volume already formatted?
    if ($volume.FileSystem -eq '')
    {
        # The volume is not formatted
        $formatVolumeParameters = @{
            FileSystem = $FSFormat
            Confirm    = $false
        }

        if ($FSLabel)
        {
            # Set the File System label on the new volume
            $formatVolumeParameters['NewFileSystemLabel'] = $FSLabel
        } # if

        if ($AllocationUnitSize)
        {
            # Set the Allocation Unit Size on the new volume
            $formatVolumeParameters['AllocationUnitSize'] = $AllocationUnitSize
        } # if

        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.FormattingVolumeMessage -f $formatVolumeParameters.FileSystem)
            ) -join '' )

        # Format the volume
        $volume = $partition | Format-Volume @formatVolumeParameters
    }
    else
    {
        # The volume is already formatted
        if ($PSBoundParameters.ContainsKey('FSFormat'))
        {
            # Check the filesystem format
            $fileSystem = $volume.FileSystem
            if ($fileSystem -ne $FSFormat)
            {
                # The file system format does not match
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.FileSystemFormatMismatch `
                                -f $DriveLetter, $fileSystem, $FSFormat)
                    ) -join '' )

                if ($AllowDestructive)
                {
                    Write-Verbose -Message ( @(
                            "$($MyInvocation.MyCommand): "
                            $($script:localizedData.VolumeFormatInProgressMessage `
                                    -f $DriveLetter, $fileSystem, $FSFormat)
                        ) -join '' )

                    $formatParam = @{
                        FileSystem = $FSFormat
                        Force      = $true
                    }

                    if ($PSBoundParameters.ContainsKey('AllocationUnitSize'))
                    {
                        $formatParam.Add('AllocationUnitSize', $AllocationUnitSize)
                    }

                    $Volume | Format-Volume @formatParam
                }
            } # if
        } # if

        # Check the volume label
        if ($PSBoundParameters.ContainsKey('FSLabel'))
        {
            # The volume should have a label assigned
            if ($volume.FileSystemLabel -ne $FSLabel)
            {
                # The volume lable needs to be changed because it is different.
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.ChangingVolumeLabelMessage `
                                -f $DriveLetter, $FSLabel)
                    ) -join '' )

                $volume | Set-Volume -NewFileSystemLabel $FSLabel
            } # if
        } # if
    } # if

    # Assign the Drive Letter if it isn't assigned
    if ($assignDriveLetter -and ($partition.DriveLetter -ne $DriveLetter))
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.AssigningDriveLetterMessage -f $DriveLetter)
            ) -join '' )

        $null = $partition | Set-Partition -NewDriveLetter $DriveLetter

        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.SuccessfullyInitializedMessage -f $DriveLetter)
            ) -join '' )
    } # if
} # Set-TargetResource

<#
    .SYNOPSIS
        Tests if the disk is initialized, the partion exists and the drive letter is assigned.
 
    .PARAMETER DriveLetter
        Specifies the preferred letter to assign to the disk volume.
 
    .PARAMETER DiskId
        Specifies the disk identifier for the disk to modify.
 
    .PARAMETER DiskIdType
        Specifies the identifier type the DiskId contains. Defaults to Number.
 
    .PARAMETER PartitionStyle
        Specifies the partition style of the disk. Defaults to GPT.
 
    .PARAMETER Size
        Specifies the size of new volume. Leave empty to use the remaining free space.
 
    .PARAMETER FSLabel
        Specifies the volume label to assign to the volume.
 
    .PARAMETER AllocationUnitSize
        Specifies the allocation unit size to use when formatting the volume.
 
    .PARAMETER FSFormat
        Specifies the file system format of the new volume.
 
    .PARAMETER AllowDestructive
        Specifies if potentially destructive operations may occur.
 
    .PARAMETER ClearDisk
        Specifies if the disks partition schema should be removed entirely, even if data and OEM
        partitions are present. Only possible with AllowDestructive enabled.
#>

function Test-TargetResource
{
    [CmdletBinding()]
    [OutputType([System.Boolean])]
    param
    (
        [Parameter(Mandatory = $true)]
        [System.String]
        $DriveLetter,

        [Parameter(Mandatory = $true)]
        [System.String]
        $DiskId,

        [Parameter()]
        [ValidateSet('Number', 'UniqueId', 'Guid', 'Location')]
        [System.String]
        $DiskIdType = 'Number',

        [Parameter()]
        [ValidateSet('GPT', 'MBR')]
        [System.String]
        $PartitionStyle = 'GPT',

        [Parameter()]
        [System.UInt64]
        $Size,

        [Parameter()]
        [System.String]
        $FSLabel,

        [Parameter()]
        [System.UInt32]
        $AllocationUnitSize,

        [Parameter()]
        [ValidateSet('NTFS', 'ReFS')]
        [System.String]
        $FSFormat = 'NTFS',

        [Parameter()]
        [System.Boolean]
        $AllowDestructive,

        [Parameter()]
        [System.Boolean]
        $ClearDisk
    )

    Write-Verbose -Message ( @(
            "$($MyInvocation.MyCommand): "
            $($script:localizedData.TestingDiskMessage -f $DiskIdType, $DiskId, $DriveLetter)
        ) -join '' )

    # Validate the DriveLetter parameter
    $DriveLetter = Assert-DriveLetterValid -DriveLetter $DriveLetter

    Write-Verbose -Message ( @(
            "$($MyInvocation.MyCommand): "
            $($script:localizedData.CheckDiskInitializedMessage -f $DiskIdType, $DiskId)
        ) -join '' )

    # Get the Disk using the identifiers supplied
    $disk = Get-DiskByIdentifier `
        -DiskId $DiskId `
        -DiskIdType $DiskIdType

    if (-not $disk)
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DiskNotFoundMessage -f $DiskIdType, $DiskId)
            ) -join '' )

        return $false
    } # if

    if ($disk.IsOffline)
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DiskNotOnlineMessage -f $DiskIdType, $DiskId)
            ) -join '' )

        return $false
    } # if

    if ($disk.IsReadOnly)
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DiskReadOnlyMessage `
                        -f $DiskIdType, $DiskId)
            ) -join '' )

        return $false
    } # if

    if ($disk.PartitionStyle -ne $PartitionStyle)
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DiskPartitionStyleNotMatchMessage `
                        -f $DiskIdType, $DiskId, $disk.PartitionStyle, $PartitionStyle)
            ) -join '' )

        if ($disk.PartitionStyle -eq 'RAW' -or ($AllowDestructive -and $ClearDisk))
        {
            return $false
        }
        else
        {
            # This disk is initialized but with the incorrect partition style
            New-InvalidOperationException `
                -Message ($script:localizedData.DiskInitializedWithWrongPartitionStyleError `
                    -f $DiskIdType, $DiskId, $disk.PartitionStyle, $PartitionStyle)
        }
    } # if

    $partition = Get-Partition `
        -DriveLetter $DriveLetter `
        -ErrorAction SilentlyContinue | Select-Object -First 1

    if ($partition.DriveLetter -ne $DriveLetter)
    {
        Write-Verbose -Message ( @(
                "$($MyInvocation.MyCommand): "
                $($script:localizedData.DriveLetterNotFoundMessage -f $DriveLetter)
            ) -join '' )

        return $false
    } # if

    # Check the partition size
    if ($partition -and -not ($PSBoundParameters.ContainsKey('Size')))
    {
        $supportedSize = ($partition | Get-PartitionSupportedSize)

        <#
            If the difference in size between the supported partition size
            and the current partition size is less than 1MB then set the
            desired partition size to the current size. This will prevent
            any size difference less than 1MB from trying to contiuously
            resize. See https://github.com/dsccommunity/StorageDsc/issues/181
        #>

        if (($supportedSize.SizeMax - $partition.Size) -lt 1MB)
        {
            $Size = $partition.Size
        }
        else
        {
            $Size = $supportedSize.SizeMax
        }
    }

    if ($Size)
    {
        if ($partition.Size -ne $Size)
        {
            # The partition size mismatches
            if ($AllowDestructive)
            {
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.SizeMismatchWithAllowDestructiveMessage `
                                -f $DriveLetter, $Partition.Size, $Size)
                    ) -join '' )

                return $false
            }
            else
            {
                Write-Verbose -Message ( @(
                        "$($MyInvocation.MyCommand): "
                        $($script:localizedData.SizeMismatchMessage `
                                -f $DriveLetter, $Partition.Size, $Size)
                    ) -join '' )
            }
        } # if
    } # if

    $blockSize = (Get-CimInstance `
            -Query "SELECT BlockSize from Win32_Volume WHERE DriveLetter = '$($DriveLetter):'" `
            -ErrorAction SilentlyContinue).BlockSize

    if ($blockSize -gt 0 -and $AllocationUnitSize -ne 0)
    {
        if ($AllocationUnitSize -ne $blockSize)
        {
            # The allocation unit size mismatches
            Write-Verbose -Message ( @(
                    "$($MyInvocation.MyCommand): "
                    $($script:localizedData.AllocationUnitSizeMismatchMessage `
                            -f $DriveLetter, $($blockSize.BlockSize / 1KB), $($AllocationUnitSize / 1KB))
                ) -join '' )

            if ($AllowDestructive)
            {
                return $false
            }
        } # if
    } # if

    # Get the volume so the properties can be checked
    $volume = Get-Volume `
        -DriveLetter $DriveLetter `
        -ErrorAction SilentlyContinue

    if ($PSBoundParameters.ContainsKey('FSFormat'))
    {
        # Check the filesystem format
        $fileSystem = $volume.FileSystem
        if ($fileSystem -ne $FSFormat)
        {
            Write-Verbose -Message ( @(
                    "$($MyInvocation.MyCommand): "
                    $($script:localizedData.FileSystemFormatMismatch `
                            -f $DriveLetter, $fileSystem, $FSFormat)
                ) -join '' )

            if ($AllowDestructive)
            {
                return $false
            }
        } # if
    } # if

    if ($PSBoundParameters.ContainsKey('FSLabel'))
    {
        # Check the volume label
        $label = $volume.FileSystemLabel
        if ($label -ne $FSLabel)
        {
            # The assigned volume label is different and needs updating
            Write-Verbose -Message ( @(
                    "$($MyInvocation.MyCommand): "
                    $($script:localizedData.DriveLabelMismatch `
                            -f $DriveLetter, $label, $FSLabel)
                ) -join '' )

            return $false
        } # if
    } # if

    return $true
} # Test-TargetResource

Export-ModuleMember -Function *-TargetResource