Monitor the UNMAP/TRIM effect on a thin provisioned SAN

Introduction

During demo’s I give on the effectiveness of storage efficiencies (UNMAP, ODX) in Hyper-V I use some PowerShell code to help show his. Trim in the virtual machine and on the Hyper-V host pass along information about deleted blocks to a thin provisioned storage array. That means that every layer can be as efficient as possible. Here’s a picture of me doing a demo to monitor the UNMAP/TRIM effect on a thin provisioned SAN.

clip_image002

The script shows how a thin provisioned LUN on a SAN (DELL SC Series) grows in actual used spaced when data is being created or copied inside VMs. When data is hard deleted TRIM/UNMAP prevents dynamically expanding VHDX files form growing more than they need to. When a VM is shut down it even shrinks. The same info is passed on to the storage array. So, when data is deleted we can see the actual space used in a thin provisioned LUN on the SAN go down. That makes for a nice demo. I have some more info on the benefits and the potential issues of UNMAP if used carelessly here.

Scripting options for the DELL SC Series (Compellent)

Your storage array needs to support thin provisioning and TRIM/UNMAP with Windows Server Hyper-V. If so all you need is PowerShell library your storage vendor must provide. For the DELL Compellent series that use to be the PowerShell Command Set (2008) which made them an early adopter of PowerShell automation in the industry. That evolved with the array capabilities and still works to day with the older SC series models. In 2015, Dell Storage introduced the Enterprise Manager API (EM-API) and also the Dell Storage PowerShell SDK, which uses the EM-API. This works over a EM Data Collector server and no longer directly to the management IP of the controllers. This is the only way to work for the newer SC series models.

It’s a powerful tool to have and allows for automation and orchestration of your storage environment when you have wrapped your head around the PowerShell commands.

That does mean that I needed to replace my original PowerShell Command Set scripts. Depending on what those scripts do this can be done easily and fast or it might require some more effort.

Monitoring UNMAP/TRIM effect on a thin provisioned SAN with PowerShell

As a short demo let me show case the Command Set and the DELL Storage PowerShell SDK version of a script monitor the UNMAP/TRIM effect on a thin provisioned SAN with PowerShell.

Command Set version

Bar the way you connect to the array the difference is in the commandlets. In Command Set retrieving the storage info is done as follows:

$SanVolumeToMonitor = “MyDemoSANVolume”

#Get the size of the volume
$CompellentVolumeSize = (Get-SCVolume -Name $SanVolumeToMonitor).Size

#Get the actual disk space consumed in that volume
$CompellentVolumeReakDiskSpaceUsed = (Get-SCVolume -Name $SanVolumeToMonitor).TotalDiskSpaceConsumed

In the DELL Storage PowerShell SDK version it is not harder, just different than it used to be.

$SanVolumeToMonitor = “MyDemoSANVolume”
$Volume = Get-DellScVolume -StorageCenter $StorageCenter -Name $SanVolumeToMonitor

$VolumeStats = Get-DellScVolumeStorageUsage -Instance $Volume.InstanceID

#Get the size of the volume
$CompellentVolumeSize = ($VolumeStats).ConfiguredSpace

#Get the actual disk space consumed in that volume
$CompellentVolumeRealDiskSpaceUsed = ($VolumeStats).ActiveSpace

Which gives …

clip_image004

I hope this gave you some inspiration to get started automating your storage provisioning and governance. On premises or cloud, a GUI and a click have there place, but automation is the way to go. As a bonus, the complete script is below.

#region PowerShell to keep the PoSh window on top during demos
$signature = @’ 
[DllImport("user32.dll")] 
public static extern bool SetWindowPos( 
    IntPtr hWnd, 
    IntPtr hWndInsertAfter, 
    int X, 
    int Y, 
    int cx, 
    int cy, 
    uint uFlags); 
‘@ 
$type = Add-Type -MemberDefinition $signature -Name SetWindowPosition -Namespace SetWindowPos -Using System.Text -PassThru

$handle = (Get-Process -id $Global:PID).MainWindowHandle 
$alwaysOnTop = New-Object -TypeName System.IntPtr -ArgumentList (-1) 
$type::SetWindowPos($handle, $alwaysOnTop, 0, 0, 0, 0, 0x0003) | Out-null
#endregion

function WriteVirtualDiskVolSize () {
    $Volume = Get-DellScVolume -Connection $Connection -StorageCenter $StorageCenter -Name $SanVolumeToMonitor
    $VolumeStats = Get-DellScVolumeStorageUsage -Connection $Connection -Instance $Volume.InstanceID
       
    #Get the size of the volume
    $CompellentVolumeSize = ($VolumeStats).ConfiguredSpace
    #Get the actual disk space consumed in that volume.
    $CompellentVolumeRealDiskSpaceUsed = ($VolumeStats).ActiveSpace

    Write-Host -Foregroundcolor Magenta "Didier Van Hoye - Microsoft MVP / Veeam Vanguard
& Dell Techcenter Rockstar"
    Write-Host -Foregroundcolor Magenta "Hyper-V, Clustering, Storage, Azure, RDMA, Networking"
    Write-Host -Foregroundcolor Magenta  "http:/blog.workinghardinit.work"
    Write-Host -Foregroundcolor Magenta  "@workinghardinit"
    Write-Host -Foregroundcolor Cyan "DELLEMC Storage Center model $SCModel version" $SCVersion.version
    Write-Host -Foregroundcolor Cyan  "Dell Storage PowerShell SDK" (Get-Module DellStorage.ApiCommandSet).version
    Write-host -foregroundcolor Yellow "
 _   _  _   _  __  __     _     ____   
| | | || \ | ||  \/  |   / \   |  _ \ 
| | | ||  \| || |\/| |  / _ \  | |_) |
| |_| || |\  || |  | | / ___ \ |  __/
 \___/ |_| \_||_|  |_|/_/   \_\|_|
"
    Write-Host ""-ForegroundColor Red
    Write-Host "Size Of the LUN on SAN: $CompellentVolumeSize" -ForegroundColor Red
    Write-Host "Space Actually Used on SAN: $CompellentVolumeRealDiskSpaceUsed" -ForegroundColor Green 

    #Wait a while before you run these queries again.
    Start-Sleep -Milliseconds 1000
}

#If the Storage Center module isn't loaded, do so!
if (!(Get-Module DellStorage.ApiCommandSet)) {    
    import-module "C:\SysAdmin\Tools\DellStoragePowerShellSDK\DellStorage.ApiCommandSet.dll"
}

$DsmHostName = "MyDSMHost.domain.local"
$DsmUserName = "MyAdminName"
$DsmPwd = "MyPass"
$SCName = "MySCName"
# Prompt for the password
$DsmPassword = (ConvertTo-SecureString -AsPlainText $DsmPwd -Force)

# Create the connection
$Connection = Connect-DellApiConnection -HostName $DsmHostName `
    -User $DsmUserName `
    -Password $DsmPassword

$StorageCenter = Get-DellStorageCenter -Connection $Connection -name $SCName 
$SCVersion = $StorageCenter | Select-Object Version
$SCModel = (Get-DellScController -Connection $Connection -StorageCenter $StorageCenter -InstanceName "Top Controller").model.Name.toupper()

$SanVolumeToMonitor = "MyDemoSanVolume"

#Just let the script run in a loop indefinitely.
while ($true) {
    Clear-Host
    WriteVirtualDiskVolSize
}

 

Collect cluster nodes with HBA WWN info

Introduction

Below is a script that I use to collect cluster nodes with HBA WWN info. It grabs the cluster nodes and their HBA (virtual ports) WWN information form an existing cluster. In this example the nodes have Fibre Channel (FC) HBAs. It works equally well for iSCSI HBA or other cards. You can use the collected info in real time. As an example I also demonstrate writing and reading the info to and from a CSV.

This script comes in handy when you are replacing the storage arrays. You’ll need that info to do the FC zoning for example.  And to create the cluster en server object with the correct HBA on the new storage arrays if it allows for automation. As a Hyper-V cluster admin you can grab all that info from your cluster nodes without the need to have access to the SAN or FC fabrics. You can use it yourself and hand it over to those handling them, who can use if to cross check the info they see on the switch or the old storage arrays.

image

Script to collect cluster nodes with HBA WWN info

The script demos a single cluster but you could use it for many. It collects the cluster name, the cluster nodes and their Emulex HBAs. It writes that information to a CSV files you can read easily in an editor or Excel.

image

The scripts demonstrates reading that CSV file and parsing the info. That info can be used in PowerShell to script the creation of the cluster and server objects on your SAN and add the HBAs to the server objects. I recently used it to move a bunch of Hyper-V and File clusters to a new DELLEMC SC Series storage arrays. That has the DELL Storage PowerShell SDK. You might find it useful as an example and to to adapt for your own needs (iSCSI, brand, model of HBA etc.).

#region Supporting Functions
Function Convert-OutputForCSV {
    <#
        .SYNOPSIS
            Provides a way to expand collections in an object property prior
            to being sent to Export-Csv.

        .DESCRIPTION
            Provides a way to expand collections in an object property prior
            to being sent to Export-Csv. This helps to avoid the object type
            from being shown such as system.object[] in a spreadsheet.

        .PARAMETER InputObject
            The object that will be sent to Export-Csv

        .PARAMETER OutPropertyType
            This determines whether the property that has the collection will be
            shown in the CSV as a comma delimmited string or as a stacked string.

            Possible values:
            Stack
            Comma

            Default value is: Stack

        .NOTES
            Name: Convert-OutputForCSV
            Author: Boe Prox
            Created: 24 Jan 2014
            Version History:
                1.1 - 02 Feb 2014
                    -Removed OutputOrder parameter as it is no longer needed; inputobject order is now respected 
                    in the output object
                1.0 - 24 Jan 2014
                    -Initial Creation

        .EXAMPLE
            $Output = 'PSComputername','IPAddress','DNSServerSearchOrder'

            Get-WMIObject -Class Win32_NetworkAdapterConfiguration -Filter "IPEnabled='True'" |
            Select-Object $Output | Convert-OutputForCSV | 
            Export-Csv -NoTypeInformation -Path NIC.csv    
            
            Description
            -----------
            Using a predefined set of properties to display ($Output), data is collected from the 
            Win32_NetworkAdapterConfiguration class and then passed to the Convert-OutputForCSV
            funtion which expands any property with a collection so it can be read properly prior
            to being sent to Export-Csv. Properties that had a collection will be viewed as a stack
            in the spreadsheet.        
            
    #>
    #Requires -Version 3.0
    [cmdletbinding()]
    Param (
        [parameter(ValueFromPipeline)]
        [psobject]$InputObject,
        [parameter()]
        [ValidateSet('Stack', 'Comma')]
        [string]$OutputPropertyType = 'Stack'
    )
    Begin {
        $PSBoundParameters.GetEnumerator() | ForEach {
            Write-Verbose "$($_)"
        }
        $FirstRun = $True
    }
    Process {
        If ($FirstRun) {
            $OutputOrder = $InputObject.psobject.properties.name
            Write-Verbose "Output Order:`n $($OutputOrder -join ', ' )"
            $FirstRun = $False
            #Get properties to process
            $Properties = Get-Member -InputObject $InputObject -MemberType *Property
            #Get properties that hold a collection
            $Properties_Collection = @(($Properties | Where-Object {
                        $_.Definition -match "Collection|\[\]"
                    }).Name)
            #Get properties that do not hold a collection
            $Properties_NoCollection = @(($Properties | Where-Object {
                        $_.Definition -notmatch "Collection|\[\]"
                    }).Name)
            Write-Verbose "Properties Found that have collections:`n $(($Properties_Collection) -join ', ')"
            Write-Verbose "Properties Found that have no collections:`n $(($Properties_NoCollection) -join ', ')"
        }
 
        $InputObject | ForEach {
            $Line = $_
            $stringBuilder = New-Object Text.StringBuilder
            $Null = $stringBuilder.AppendLine("[pscustomobject] @{")

            $OutputOrder | ForEach {
                If ($OutputPropertyType -eq 'Stack') {
                    $Null = $stringBuilder.AppendLine("`"$($_)`" = `"$(($line.$($_) | Out-String).Trim())`"")
                }
                ElseIf ($OutputPropertyType -eq "Comma") {
                    $Null = $stringBuilder.AppendLine("`"$($_)`" = `"$($line.$($_) -join ', ')`"")                   
                }
            }
            $Null = $stringBuilder.AppendLine("}")
 
            Invoke-Expression $stringBuilder.ToString()
        }
    }
    End {}
}
function Get-WinOSHBAInfo {
<#
Basically add 3 nicely formated properties to the HBA info we get via WMI
These are the NodeWWW, the PortWWN and the FabricName. The raw attributes
from WMI are not readily consumable. WWNs are given with a ":" delimiter.
This can easiliy be replaced or removed depending on the need.
#>

param ($ComputerName = "localhost")
 
# Get HBA Information
$Port = Get-WmiObject -ComputerName $ComputerName -Class MSFC_FibrePortHBAAttributes -Namespace "root\WMI"
$HBAs = Get-WmiObject -ComputerName $ComputerName -Class MSFC_FCAdapterHBAAttributes  -Namespace "root\WMI"
 
$HBAProperties = $HBAs | Get-Member -MemberType Property, AliasProperty | Select -ExpandProperty name | ? {$_ -notlike "__*"}
$HBAs = $HBAs | Select-Object $HBAProperties
$HBAs | % { $_.NodeWWN = ((($_.NodeWWN) | % {"{0:x2}" -f $_}) -join ":").ToUpper() }
 
ForEach ($HBA in $HBAs) {
 
    # Get Port WWN
    $PortWWN = (($Port |? { $_.instancename -eq $HBA.instancename }).attributes).PortWWN
    $PortWWN = (($PortWWN | % {"{0:x2}" -f $_}) -join ":").ToUpper()
    Add-Member -MemberType NoteProperty -InputObject $HBA -Name PortWWN -Value $PortWWN
    # Get Fabric WWN
    $FabricWWN = (($Port |? { $_.instancename -eq $HBA.instancename }).attributes).FabricName
    $FabricWWN = (($FabricWWN | % {"{0:x2}" -f $_}) -join ":").ToUpper()
    Add-Member -MemberType NoteProperty -InputObject $HBA -Name FabricWWN -Value $FabricWWN
 
    # Output
    $HBA
}
}
#endregion 

#Grab the cluster nane in a variable. Adapt thiscode to loop through all your clusters.
$ClusterName = "DEMOLABCLUSTER"
#Grab all cluster node 
$ClusterNodes = Get-Cluster -name $ClusterName | Get-ClusterNode
#Create array of custom object to store ClusterName, the cluster nodes and the HBAs
$ServerWWNArray = @()

ForEach ($ClusterNode in $ClusterNodes) {
    #We loop through the cluster nodes the cluster and for each one we grab the HBAs that are relevant.
    #My lab nodes have different types installed up and off, so I specify the manufacturer to get the relevant ones.
    #Adapt to your needs. You ca also use modeldescription to filter out FCoE vers FC HBAs etc.
    $AllHBAPorts = Get-WinOSHBAInfo -ComputerName $ClusterNode.Name | Where-Object {$_.Manufacturer -eq "Emulex Corporation"} 

    #The SC Series SAN PowerShell takes the WWNs without any delimiters, so we dump the ":" for this use case.
    $WWNs = $AllHBAPorts.PortWWN -replace ":", ""
    $NodeName = $ClusterNode.Name

    #Build a nice node object with the info and add it to the $ServerWWNArray 
    $ServerWWNObject = New-Object psobject -Property @{
        WWN         = $WWNs
        ServerName  = $NodeName 
        ClusterName = $ClusterName         
    }
    $ServerWWNArray += $ServerWWNObject
}

#Show our array
$ServerWWNArray

#just a demo to list what's in the array
ForEach ($ServerNode in $ServerWWNArray) {    
    $Servernode.ServerName
    
    ForEach ($WWN in $Servernode.WWN)
    {$WWN}

}

#Show the results
$Export = $ServerWWNArray | Convert-OutputForCSV
#region write to CSV and read from CSV

#You can dump this in a file
$Export | export-csv -Path "c:\SysAdmin\$ClusterName.csv" -Delimiter ";"

#and get it back from a file
Get-Content -Path "c:\SysAdmin\$ClusterName.csv"
$ClusterInfoFile = Import-CSV -Path "c:\SysAdmin\$ClusterName.csv" -Delimiter ";"
$ClusterInfoFile | Format-List

#just a demo to list what's in the array
$MyClusterName = $ClusterInfoFile.clustername | get-unique
$MyClusterName
ForEach ($ClusterNode in $ClusterInfoFile) {  

    $ClusterNode.ServerName
    
    ForEach ($WWN in $ClusterNode.WWN) {
        $WWN
    }

}

Add HBAs to SC Series Servers with Add-DellScPhysicalServerHba

Introduction

Before I dump the script to add HBAs to SC Series Servers with Add-DellScPhysicalServerHba on you, first some context. I have been quite busy with multiple SAN migrations. A bunch of older DELLEMC SC Series (Compellent) to newer All Flash Arrays (see My first Dell SC7020(F) Array Solution)  When I find the time I’ll share some more PowerShell snippets I use to make such efforts a bit easier. It’s quite addictive and it allows you migrate effectively and efficiently.

In the SC Series we create cluster objects in which we place server objects. That make life easier on the SAN end.image

Those server objects are connected to the SAN via FC or iSCSI. For this we need to add the HBAs to the servers after we have set up the zoning correctly. That’s a whole different subject.

image

This is tedious work in the user interface, especially when there are many WWN entries visible that need to be assigned. Mistakes can happen. This is where automation comes in handy and a real time saver when you have many clusters/nodes and multiple SANs. So well show you how to grab the WWN info your need from the cluster nodes to add HBAs to SC Series Servers with Add-DellScPhysicalServerHba.

Below you see a script that loops through all the nodes of a cluster and gets the HBA WWNs we need. I than adds those WWNs to the SC Series server object. In another blog post I’ll share so snippets to gather the cluster info needed to create the cluster objects and server objects on the Compellent SC Series SAN. In this blog post we’ll assume the server have objects has been created.

We leverage the Dell Storage Manager – 2016 R3.20 Release (Public PowerShell SDK for Dell Storage API). I hope it helps.

Add HBAs to SC Series Servers with Add-DellScPhysicalServerHba

function Get-WinOSHBAInfo
#Basically add 3 nicely formated properties to the HBA info we get via WMI
#These are the NodeWWW, the PortWWN and the FabricName. The raw attributes
#from WMI are not readily consumable. WWNs are given with a ":" delimiter.
#This can easiliy be replaced or removed depending on the need. 
{ 
param ($ComputerName = "localhost")
 
# Get HBA Information
$Port = Get-WmiObject -ComputerName $ComputerName -Class MSFC_FibrePortHBAAttributes -Namespace "root\WMI"
$HBAs = Get-WmiObject -ComputerName $ComputerName -Class MSFC_FCAdapterHBAAttributes  -Namespace "root\WMI"
 
$HBAProperties = $HBAs | Get-Member -MemberType Property, AliasProperty | Select -ExpandProperty name | ? {$_ -notlike "__*"}
$HBAs = $HBAs | Select-Object $HBAProperties
$HBAs | % { $_.NodeWWN = ((($_.NodeWWN) | % {"{0:x2}" -f $_}) -join ":").ToUpper() }
 
ForEach ($HBA in $HBAs) {
 
    # Get Port WWN
    $PortWWN = (($Port |? { $_.instancename -eq $HBA.instancename }).attributes).PortWWN
    $PortWWN = (($PortWWN | % {"{0:x2}" -f $_}) -join ":").ToUpper()
    Add-Member -MemberType NoteProperty -InputObject $HBA -Name PortWWN -Value $PortWWN
    # Get Fabric WWN
    $FabricWWN = (($Port |? { $_.instancename -eq $HBA.instancename }).attributes).FabricName
    $FabricWWN = (($FabricWWN | % {"{0:x2}" -f $_}) -join ":").ToUpper()
    Add-Member -MemberType NoteProperty -InputObject $HBA -Name FabricWWN -Value $FabricWWN
 
    # Output
    $HBA
}
}
#Grab the cluster nane in a variable. Adapt thiscode to loop through all your clusters.
$ClusterName = "DEMOLABCLUSTER"
#Grab all cluster node 
$ClusterNodes = Get-Cluster -name $ClusterName | Get-ClusterNode

#Create array of custom object to store ClusterName, the cluster nodes and the HBAs
$ServerWWNArray = @()

ForEach ($ClusterNode in $ClusterNodes) {
    #We loop through the cluster nodes the cluster and for each one we grab the HBAs that are relevant.
    #My lab nodes have different types installed up and off, so I specify the manufacturer to get the relevant ones.
    #Adapt to your needs. You ca also use modeldescription to filter out FCoE vers FC HBAs etc.
    $AllHBAPorts = Get-WinOSHBAInfo -ComputerName $ClusterNode.Name | Where-Object {$_.Manufacturer -eq "Emulex Corporation"} 

    #The SC Series SAN PowerShell takes the WWNs without any delimiters, so we dump the ":" for this use case.
    $WWNs = $AllHBAPorts.PortWWN -replace ":", ""
    $NodeName = $ClusterNode.Name

    #Build a nice node object with the info and add it to the $ServerWWNArray 
    $ServerWWNObject = New-Object psobject -Property @{
        WWN         = $WWNs
        ServerName  = $NodeName 
        ClusterName = $ClusterName         
    }
    $ServerWWNArray += $ServerWWNObject
}

#Show our array
($ServerWWNArray).WWN

#just a demo to list what's in the array
ForEach ($ServerNode in $ServerWWNArray) {
    
    $Servernode.ServerName
    $Servernode.WWN
}

#Now add the HBA to the servers in the cluster.
#This is part of a bigger script that gathers all HBA/WWN infor for all clusters
#and creates the Compellent SC Series Cluster Object, the Servers, add the HBA's
#I'll post more snippets in futire blog post to show how to do that and give you
#some ideas for your own environment.

import-module "C:\SysAdmin\Tools\DellStoragePowerShellSDK\DellStorage.ApiCommandSet.dll"

#region SetUpDSMAccess Variable & credentials
Get-DellScController
$DsmHostName = "MyDSMHost.domain.local"
$DsmUserName = "MyUserName"
# Prompt for the password
$DsmPassword = Read-Host -AsSecureString -Prompt "Please enter the password for $DsmUserName"

# Create the connection
Connect-DellApiConnection -HostName $DsmHostName -User $DsmUserName -Password $DsmPassword -Save MyConnection 

#Assign variables
$ConnName = "MyConnection "
$ScName = "MySCName"

# Get the Storage Center
$StorageCenter = Get-DellStorageCenter -ConnectionName $ConnName -Name $ScName


ForEach ( $ClusterNodeWWNInfo in  $ServerWWNArray ) {
    # Get the server
    $Server = Get-DellScPhysicalServer -StorageCenter $StorageCenter -Name $ClusterNodeWWNInfo.ServerName
    $PortType = [DellStorage.Api.Enums.FrontEndTransportTypeEnum] "FibreChannel"
  
    ForEach ($WWN in $ClusterNodeWWNInfo.WWN)
    {
     # Add the array of WWNs for the cluster node and add them to the SC Compellent server
      Add-DellScPhysicalServerHba -ConnectionName $ConnName `
     -Instance $Server `
     -HbaPortType $PortType `
     -WwnOrIscsiName $WWN  -Confirm:$false
     }
}

 

Dell SC Series MPIO Registry Settings script

Introduction

When  you’re using DELL Compellent (SC Series) storage you might be leveraging the  Dell SC Series MPIO Registry Settings script they give you to set the recommended settings. That’s a nice little script you can test, verify and adapt to integrate into your set up scripts. You can find it in the Dell EMC SC Series Storage and Microsoft Multipath I/O

Dell SC Series MPIO Registry Settings script

Recently I was working with a new deployment ( 7.2.40) to test and verify it in a lab environment. The lab cluster nodes had a lot of NIC & FC HBA to test all kinds of possible scenarios Microsoft Windows Clusters, S2D, Hyper-V, FC and iSCSI etc. The script detected the iSCSI service but did not update any setting but did throw errors.

image

After verifying things in the registry myself it was clear that the entries for the Microsoft iSCSI Initiator that the script is looking for are there but the script did not pick them up.

image

Looking over the script it became clear quickly what the issue was. The variable $IscsiRegPath = “HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e97b-e325-11ce-bfc1-08002be10318}\000*” has 3 leading zeros out of a max of 4 characters. This means that if the Microsoft iSCSI Initiator info is in 0009 it get’s picked up but not when it is in 0011 for example.

So I changed that to only 2 leading zeros. This makes the assumption you won’t exceed 0099 which is a safer assumption, but you could argue this should even be only one leading zero as 999 is an even safer assumption.

$IscsiRegPath = “HKLM:\SYSTEM\CurrentControlSet\Control\Class\{4d36e97b-e325-11ce-bfc1-08002be10318}\00*”

I’m sharing the snippet with my adaptation here in case you want it. As always I assume nu responsibility for what you do with the script or the outcomes in your environment. Big boy rules apply.

# MPIO Registry Settings script
# This script will apply recommended Dell Storage registry settings
# on Windows Server 2008 R2 or newer
#
# THIS CODE IS MADE AVAILABLE AS IS, WITHOUT WARRANTY OF ANY KIND.
# THE ENTIRE RISK OF THE USE OR THE RESULTS FROM THE USE OF THIS CODE
# REMAINS WITH THE USER.
# Assign variables

$MpioRegPath = "HKLM:\SYSTEM\CurrentControlSet\Services\mpio\Parameters"
$IscsiRegPath = "HKLM:\SYSTEM\CurrentControlSet\Control\Class\"
#DIDIER adaption to 2 leading zeros instead of 3 as 0010 and 0011 would not be
#found otherwise.This makes the assumption you won't exceed 0099 which is a
#safer #assumption, but you could argue that this should even be only one
#leading zero as 999 is #an even #safer assumption.
$IscsiRegPath += "{4d36e97b-e325-11ce-bfc1-08002be10318}\00*"

# General settings
Set-ItemProperty -Path $MpioRegPath -Name "PDORemovePeriod" -Value 120
Set-ItemProperty -Path $MpioRegPath -Name "PathRecoveryInterval" -Value 25
Set-ItemProperty -Path $MpioRegPath -Name "UseCustomPathRecoveryInterval" -Value 1
Set-ItemProperty -Path $MpioRegPath -Name "PathVerifyEnabled" -Value 1

# Apply OS-specific general settings
$OsVersion = ( Get-WmiObject -Class Win32_OperatingSystem ).Caption
If ( $OsVersion -match "Windows Server 2008 R2" )
{
New-ItemProperty –Path $MpioRegPath –Name "DiskPathCheckEnabled" –Value 1 –PropertyType DWORD –Force
New-ItemProperty –Path $MpioRegPath –Name "DiskPathCheckInterval" –Value 25 –PropertyType DWORD –Force
}
Else
{
Set-ItemProperty –Path $MpioRegPath –Name "DiskPathCheckInterval" –Value 25
}

# iSCSI settings
If ( ( Get-Service -Name "MSiSCSI" ).Status -eq "Running" )
{
# Get the registry path for the Microsoft iSCSI initiator parameters
$IscsiParam = Get-Item -Path $IscsiRegPath | Where-Object { ( Get-ItemProperty $_.PSPath ).DriverDesc -eq "Microsoft iSCSI Initiator"} | Get-ChildItem | Where-Object { $_.PSChildName -eq "Parameters" }

# Set the Microsoft iSCSI initiator parameters
Set-ItemProperty -Path $IscsiParam.PSPath -Name "MaxRequestHoldTime" -Value 90
Set-ItemProperty -Path $IscsiParam.PSPath -Name "LinkDownTime" -Value 35
Set-ItemProperty -Path $IscsiParam.PSPath -Name "EnableNOPOut" -Value 1
}
Else
{
Write-Host "iSCSI Service is not running."
Write-Host "iSCSI registry settings have NOT been configured."
}

Write-Host "MPIO registry settings have been configured successfully."
Write-Host "The system must be restarted for the changes to take effect."