functions/Test-DbaDiskAllocation.ps1

function Test-DbaDiskAllocation {
    <#
    .SYNOPSIS
        Checks all disks on a computer to see if they are formatted with allocation units of 64KB.
 
    .DESCRIPTION
        Checks all disks on a computer for disk allocation units that match best practice recommendations. If one server is checked, only $true or $false is returned. If multiple servers are checked, each server's name and an IsBestPractice field are returned.
 
        References:
        https://technet.microsoft.com/en-us/library/dd758814(v=sql.100).aspx - "The performance question here is usually not one of correlation per the formula, but whether the cluster size has been explicitly defined at 64 KB, which is a best practice for SQL Server."
 
    .PARAMETER ComputerName
        The server(s) to check disk configuration on.
 
    .PARAMETER NoSqlCheck
        If this switch is enabled, the disk(s) will not be checked for SQL Server data or log files.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
 
        Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
 
        For MFA support, please use Connect-DbaInstance.
 
    .PARAMETER Credential
        Specifies an alternate Windows account to use when enumerating drives on the server. May require Administrator privileges. To use:
 
        $cred = Get-Credential, then pass $cred object to the -Credential parameter.
 
    .PARAMETER WhatIf
        If this switch is enabled, no actions are performed but informational messages will be displayed that explain what would happen if the command were to run.
 
    .PARAMETER Confirm
        If this switch is enabled, you will be prompted for confirmation before executing any operations that change state.
 
    .PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
    .NOTES
        Tags: CIM, Storage
        Author: Chrissy LeMaire (@cl), netnerds.net
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Test-DbaDiskAllocation
 
    .EXAMPLE
        PS C:\> Test-DbaDiskAllocation -ComputerName sqlserver2014a
 
        Scans all disks on server sqlserver2014a for best practice allocation unit size.
 
    .EXAMPLE
        PS C:\> Test-DbaDiskAllocation -ComputerName sqlserver2014 | Select-Output *
 
        Scans all disks on server sqlserver2014a for allocation unit size and returns detailed results for each.
 
    .EXAMPLE
        PS C:\> Test-DbaDiskAllocation -ComputerName sqlserver2014a -NoSqlCheck
 
        Scans all disks not hosting SQL Server data or log files on server sqlserver2014a for best practice allocation unit size.
 
    #>

    [CmdletBinding(SupportsShouldProcess)]
    [OutputType("System.Collections.ArrayList", "System.Boolean")]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [object[]]$ComputerName,
        [switch]$NoSqlCheck,
        [PSCredential]$SqlCredential,
        [PSCredential]$Credential,
        [switch]$EnableException
    )

    begin {
        $sessionoptions = New-CimSessionOption -Protocol DCOM

        function Get-AllDiskAllocation {
            $alldisks = @()
            $SqlInstances = @()

            try {
                Write-Message -Level Verbose -Message "Getting disk information from $computer."

                # $query = "Select Label, BlockSize, Name from Win32_Volume WHERE FileSystem='NTFS'"
                # $disks = Get-WmiObject -ComputerName $ipaddr -Query $query | Sort-Object -Property Name
                $disks = Get-CimInstance -CimSession $CIMsession -ClassName win32_volume -Filter "FileSystem='NTFS'" -ErrorAction Stop | Sort-Object -Property Name
            } catch {
                Stop-Function -Message "Can't connect to WMI on $computer."
                return
            }

            if ($NoSqlCheck -eq $false) {
                Write-Message -Level Verbose -Message "Checking for SQL Services"
                $sqlservices = Get-Service -ComputerName $ipaddr | Where-Object { $_.DisplayName -like 'SQL Server (*' }
                foreach ($service in $sqlservices) {
                    $instance = $service.DisplayName.Replace('SQL Server (', '')
                    $instance = $instance.TrimEnd(')')

                    $instancename = $instance.Replace("MSSQLSERVER", "Default")
                    Write-Message -Level Verbose -Message "Found instance $instancename."

                    if ($instance -eq 'MSSQLSERVER') {
                        $SqlInstances += $ipaddr
                    } else {
                        $SqlInstances += "$ipaddr\$instance"
                    }
                }
                $sqlcount = $SqlInstances.Count

                Write-Message -Level Verbose -Message "$sqlcount instance(s) found."
            }

            foreach ($disk in $disks) {
                if (!$disk.name.StartsWith("\\")) {
                    $diskname = $disk.Name

                    if ($NoSqlCheck -eq $false) {
                        $sqldisk = $false

                        foreach ($SqlInstance in $SqlInstances) {
                            try {
                                $smoserver = Connect-SqlInstance -SqlInstance $SqlInstance -SqlCredential $SqlCredential
                                $sql = "Select count(*) as Count from sys.master_files where physical_name like '$diskname%'"
                                $sqlcount = $smoserver.Databases['master'].ExecuteWithResults($sql).Tables[0].Count
                                if ($sqlcount -gt 0) {
                                    $sqldisk = $true
                                    break
                                }
                            } catch {
                                Stop-Function -Message "Error occurred while establishing connection to $instance" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
                                continue
                            }
                        }
                    }

                    if ($disk.BlockSize -eq 65536) {
                        $IsBestPractice = $true
                    } else {
                        $IsBestPractice = $false
                    }

                    $windowsdrive = "$env:SystemDrive\"

                    if ($diskname -eq $windowsdrive) {
                        $IsBestPractice = $false
                    }

                    if ($NoSqlCheck -eq $false) {
                        $alldisks += [PSCustomObject]@{
                            Server         = $computer
                            Name           = $diskname
                            Label          = $disk.Label
                            BlockSize      = $disk.BlockSize
                            IsSqlDisk      = $sqldisk
                            IsBestPractice = $IsBestPractice
                        }
                    } else {
                        $alldisks += [PSCustomObject]@{
                            Server         = $computer
                            Name           = $diskname
                            Label          = $disk.Label
                            BlockSize      = $disk.BlockSize
                            IsBestPractice = $IsBestPractice
                        }
                    }
                }
            }
            return $alldisks
        }
    }

    process {
        # uses cim commands


        foreach ($computer in $ComputerName) {

            $computer = Resolve-DbaNetworkName -ComputerName $computer -Credential $Credential
            $ipaddr = $computer.IpAddress
            $Computer = $computer.FullComputerName

            if (!$Computer) {
                Stop-Function -Message "Couldn't resolve hostname. Skipping." -Continue
            }

            Write-Message -Level Verbose -Message "Creating CimSession on $computer over WSMan."

            if (!$Credential) {
                $cimsession = New-CimSession -ComputerName $Computer -ErrorAction SilentlyContinue
            } else {
                $cimsession = New-CimSession -ComputerName $Computer -ErrorAction SilentlyContinue -Credential $Credential
            }

            if ($null -eq $cimsession.id) {
                Write-Message -Level Verbose -Message "Creating CimSession on $computer over WSMan failed. Creating CimSession on $computer over DCOM."

                if (!$Credential) {
                    $cimsession = New-CimSession -ComputerName $Computer -SessionOption $sessionoptions -ErrorAction SilentlyContinue
                } else {
                    $cimsession = New-CimSession -ComputerName $Computer -SessionOption $sessionoptions -ErrorAction SilentlyContinue -Credential $Credential
                }
            }

            if ($null -eq $cimsession.id) {
                Stop-Function -Message "Can't create CimSession on $computer" -Target $Computer
            }

            Write-Message -Level Verbose -Message "Getting Power Plan information from $Computer"

            if ($PScmdlet.ShouldProcess("$computer", "Getting Disk Allocation")) {
                $data = Get-AllDiskAllocation $computer

                if ($data.Count -gt 1) {
                    $data.GetEnumerator()
                } else {
                    $data
                }
            }
        }
    }
}