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.
             
            Specify -Detailed for details.
             
            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."
             
            http://tk.azurewebsites.net/2012/08/
             
        .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
            Allows you to login to servers using SQL Logins instead of Windows Authentication (AKA Integrated or Trusted). To use:
 
            $scred = Get-Credential, then pass $scred object to the -SqlCredential parameter.
 
            Windows Authentication will be used if SqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
 
            To connect as a different Windows user, run PowerShell as that user.
         
        .PARAMETER Detailed
            Output all properties, will be deprecated in 1.0.0 release.
 
        .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
            Requires: Windows sysadmin access on SQL Servers
                 
            dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
            Copyright (C) 2016 Chrissy LeMaire
            License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
        .LINK
            https://dbatools.io/Test-DbaDiskAllocation
 
        .EXAMPLE
            Test-DbaDiskAllocation -ComputerName sqlserver2014a
 
            Scans all disks on server sqlserver2014a for best practice allocation unit size.
 
        .EXAMPLE
            Test-DbaDiskAllocation -ComputerName sqlserver2014 | Select-Output *
             
            Scans all disks on server sqlserver2014a for allocation unit size and returns detailed results for each.
             
        .EXAMPLE
            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 = $true)]
    [OutputType("System.Collections.ArrayList", "System.Boolean")]
    Param (
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer", "SqlInstance")]
        [object[]]$ComputerName,
        [switch]$NoSqlCheck,
        [object]$SqlCredential,
        [switch]$Detailed,
        [switch][Alias('Silent')]$EnableException
    )
    
    begin {
        Test-DbaDeprecation -DeprecatedOn 1.0.0 -Parameter Detailed        
        
        $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 $SqlInstances) {
                            Write-Message -Level Verbose -Message "Connecting to SQL instance ($SqlInstance)."
                            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 "Failure" -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 {
        foreach ($computer in $ComputerName) {
            
            $computer = Resolve-DbaNetworkName -ComputerName $computer -Credential $credential
            $ipaddr = $computer.IpAddress
            $Computer = $computer.ComputerName
            
            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 $sessionoption -ErrorAction SilentlyContinue -Credential $Credential
                }
                else {
                    $cimsession = New-CimSession -ComputerName $Computer -SessionOption $sessionoption -ErrorAction SilentlyContinue
                }
            }
            
            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"
            
            $data = Get-AllDiskAllocation $computer
                        
            if ($data.Count -gt 1) {
                $data.GetEnumerator()
            }
            else {
                $data
            }
        }
    }
}