VMGuru.com

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

Param (
    [string] $vmName,
    [string] $vimHost,
    [string] $vimUser,
    [string] $vimPass,
    [Boolean] $enableCBT = $false
 
)
#Use the optional $enableCBT paramater at input to enable CBT on
#a compatible virtual machine (HW Version 7). In order for CBT flags to take 
#effect, a Snapshot must be added and removed.
function Add-CBTFlag {
    if ($vmv.Config.ChangeTrackingEnabled){
        "CBT is already enabled on $vm"
        return
    }
    $vmConfigSpec = New-Object VMware.Vim.VirtualMachineConfigSpec
    $vmConfigSpec.changeTrackingEnabled = $true
    $vmv.ReconfigVM($vmConfigSpec)
    sleep 3
    $vm | New-Snapshot -Name "Enable CBT"
    sleep 5
    $vm | Get-Snapshot -Name "Enable CBT" | Remove-Snapshot -Confirm:$false
    "Enabled CBT for $vm"
}
 
#Add a snapshot specific to the purposes of this script
function Add-CBTSnap {
    $newSnap = $vm | New-Snapshot -Name "CBT Change Tracker"
    return $newSnap
}
 
#Remove the snapshot created for the purpose of this script
function Remove-CBTSnap {
    param (
        $vmSnap
    )
    $vmSnap | Remove-Snapshot -Confirm:$false
}
 
#Captures the ChangeID of the snapshot, which is required for comparisson 
#tracking purposes.  The current run of the script will always compare
#current state against the previously logged ChangeID for differences.
function Get-ChangeID {
    param (
        $vmSnap
    )
    $vmSnapv.Config.Hardware.Device | where {($_.GetType()).Name -eq "VirtualDisk"} | ForEach-Object {
        $vzCBT = New-Object PSObject
        $vzCBT.PSObject.TypeNames.Clear()
        $vzCBT.PSObject.TypeNames.Insert(0,"vzCBTTracker")
        $vzCBT `
            | Add-Member -MemberType NoteProperty -Name VMName -Value $vm.Name -PassThru `
            | Add-Member -MemberType NoteProperty -Name DeviceID -Value $_.Key -PassThru `
            | Add-Member -MemberType NoteProperty -Name ChangeID -Value $_.Backing.Get_ChangeID()
        [array] $vzCBTColl += $vzCBT
    }
    return $vzCBTColl
}
 
#Writes the historic ChangeID and VMDK device information to a tracking file
#This file is read on each iteration of the script to capture the previos
#iterations ChangeID inforation.
function Write-TrackerLog {
    $output = $null
    $cid | ForEach-Object {
        $output += $_.VMName + "," + $_.DeviceID + "," + $_.ChangeID + "`n"
    }
    $output | Out-File "$vm-CBTTracker.cfg"
}
 
#Reads previous state information of the VM from the Tracker.cfg file
#Captures the list of changed blocks for the specified VM for each VMDK file
#calculates the total size in bytes of changed block data across all VMDK
#files associated with the VM.
function Get-ChangedBlockSize {
    $chSize = 0
    Get-Content "$vm-CBTTracker.cfg" | ForEach-Object {
        if ($_ -ne "") {
            $TrackerRef = $_.split(",")
            $changes = $vmv.QueryChangedDiskAreas($vmSnapv.MoRef,$TrackerRef[1],0,$TrackerRef[2])
            $changes.ChangedArea | ForEach-Object {
                $chSize += $_.Length
            }
        }
    }
    $chSize = $chSize/1024/1024
    return $chSize
}
 
#Writes the actual iterations change data out to a CSV file
function Write-TrackerCSV {
    $longDate = Get-Date
    $shortDate = $longDate.toShortDateString() + " - " + $longdate.toShortTimeString()
    Add-Content "$vm-CBTTracker.csv" "$vm,$shortDate,$amtChanged"
}
 
#Loads VMware's PowerCLI PowerShell Cmdlets if necessary
[void](Get-PSSnapin VMWare.VimAutomation.Core -ErrorVariable getVmwareSnapinErr 2> $null)
if ($getVmwareSnapinErr.Count -gt 0) {    Add-PSSnapin VMware.VimAutomation.Core }
 
#Establish a connection to the VI Server based on input parameters
Connect-VIServer $vimHost -User $vimUser -Password $vimPass
 
#Load some VM variables
$vm = Get-VM $vmName
$vmv = $vm | Get-View
 
#We can only run against a single VM at this point in time.  This makes sure
#the object being passed is a single VirtualMachineImpl object, and not a 
#collection.
if (($vm.GetType()).Name -ne "VirtualMachineImpl"){
    "Script can only run against a single VM at a time"
    return
}
 
#Checks to make sure VM Hardware version is 7.  Terminates if not.
if ($vmv.Config.Version -ne "vmx-07" -and $vmv.Config.Version -ne "vmx-08"){
    "The Virtual Machine $vm must be VM Hardware Version 7 to support CBT"
    return
}
 
#If the "-enableCBT $true" flag is set as an input parameter, enables CBT 
#for specified VM if necessary
if ($enableCBT){
    Add-CBTFlag
}
 
#If all other checks fail, this is a final failsafe to ensure CBT is enabled
#on the VM before continuing the script.
if ($vmv.Config.ChangeTrackingEnabled -eq $false){
    "CBT is not enabled on $vm.  Script cannot proceed."
    return
}
 
#Load up snapshot variables
$vmSnap = Add-CBTSnap
$vmSnapv = $vmSnap | Get-View
$amtChanged = 0
 
#Checks to see if the script has previous written out a CBTTracker.cfg file. This
#would indicate file deletion, or first script run.  If cfg file doesn't exist,
#initializes CSV headings.  If this is an iterative run, Gets the amount of
#data that has changed since previous iteration.  Writes to CSV file.
if (Test-Path "$vm-CBTTracker.cfg") {
    $amtChanged = Get-ChangedBlockSize
    Write-TrackerCSV
}
else {
    Add-Content "$vm-CBTTracker.csv" "VMName,Time,ChangedMB"
}
 
#Capsture the current ChangeID to use against next iteration, Remove Snapshot
#Write cfg data.
$cid = Get-ChangeID ($vmSnap)
Remove-CBTSnap ($vmSnap)
Write-TrackerLog