functions/Test-DbaPowerPlan.ps1

Function Test-DbaPowerPlan
{
<#
.SYNOPSIS
Checks SQL Server Power Plan, which Best Practices recommends should be set to High Performance
    
.DESCRIPTION
Returns $true or $false by default for one server. Returns Server name and IsBestPractice for more than one server.
    
Specify -Detailed for details.
    
References:
https://support.microsoft.com/en-us/kb/2207548
http://www.sqlskills.com/blogs/glenn/windows-power-plan-effects-on-newer-intel-processors/
    
.PARAMETER ComputerName
The SQL Server (or server in general) that you're connecting to. The -SqlServer parameter also works.
    
.PARAMETER CustomPowerPlan
If your organization uses a custom power plan that's considered best practice, specify it here.

.PARAMETER Detailed
Show a detailed list.

.PARAMETER WhatIf
Shows what would happen if the command were to run. No actions are actually performed.

.PARAMETER Confirm
Prompts you for confirmation before executing any changing operations within the command.

.NOTES
Requires: WMI access to servers
    
dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
Copyright (C) 2016 Chrissy LeMaire

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

.LINK
https://dbatools.io/Test-DbaPowerPlan

.EXAMPLE
Test-DbaPowerPlan -ComputerName sqlserver2014a

To return true or false for Power Plan being set to High Performance

.EXAMPLE
Test-DbaPowerPlan -ComputerName sqlserver2014a -CustomPowerPlan 'Maximum Performance'

To return true or false for Power Plan being set to the custom power plan called Maximum Performance

.EXAMPLE
Test-DbaPowerPlan -ComputerName sqlserver2014a -Detailed
    
To return detailed information Power Plans
    
#>

    [CmdletBinding(SupportsShouldProcess = $true)]
    Param (
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlInstance", "SqlServer")]
        [string[]]$ComputerName,
        [string]$CustomPowerPlan,
        [switch]$Detailed
    )
    
    BEGIN
    {
        $bpPowerPlan = [PSCustomObject]@{
            InstanceID = '8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c'
            ElementName = $null
        }
                    
        Function Get-PowerPlan
        {
            try
            {
                Write-Verbose "Testing connection to $server and resolving IP address"
                $ipaddr = (Test-Connection $server -Count 1 -ErrorAction SilentlyContinue).Ipv4Address | Select-Object -First 1                
            }
            catch
            {
                Write-Warning "Can't connect to $server"
                return
            }
            
            try
            {                
                Write-Verbose "Getting Power Plan information from $server"
                $powerplans = $(Get-CimInstance -ComputerName $ipaddr -classname Win32_PowerPlan -Namespace "root\cimv2\power" | select ElementName, InstanceID, IsActive)                
                $powerplan = $($powerplans | where {  $_.IsActive -eq 'True' } |  select ElementName, InstanceID)
                $powerplan.InstanceID = $powerplan.InstanceID.Split('{')[1].Split('}')[0]
                
                if ($CustomPowerPlan.Length -gt 0)
                {                    
                    $bpPowerPlan.ElementName = $CustomPowerPlan
                    $bpPowerPlan.InstanceID = $( $powerplans | where {  $_.ElementName -eq $CustomPowerPlan }).InstanceID
                }
                else 
                {
                    $bpPowerPlan.ElementName =  $( $powerplans | where {  $_.InstanceID.Split('{')[1].Split('}')[0] -eq $bpPowerPlan.InstanceID }).ElementName  
                    if ($bpPowerplan.ElementName -eq $null)
                    {
                        $bpPowerPlan.ElementName = "You do not have the high performance plan installed on this machine."
                    }
                }

            }
            catch 
            {
                Write-Warning "Can't connect to WMI on $server"
                return
            }
            
            Write-Verbose "Recommended GUID is $($bpPowerPlan.InstanceID) and you have $($powerplan.InstanceID)"
            if ($powerplan.InstanceID -eq $null)
            {
                # the try/catch above isn't working, so make it silent and handle it here.
                $powerplan.ElementName = "Unknown"
            }
            
            if ($powerplan.InstanceID -eq $bpPowerPlan.InstanceID)
            {                
                $IsBestPractice = $true
            }
            else
            {
                $IsBestPractice = $false
            }
            
            $planinfo = [PSCustomObject]@{
                Server = $server
                ActivePowerPlan = $powerplan.ElementName
                RecommendedPowerPlan = $bpPowerPlan.ElementName
                IsBestPractice = $IsBestPractice
            }
            return $planinfo
        }
        
        $collection = New-Object System.Collections.ArrayList
        $processed = New-Object System.Collections.ArrayList
    }
    
    PROCESS
    {
        foreach ($server in $ComputerName)
        {
            if ($server -match '\\')
            {
                Write-Verbose "SQL Server naming convention detected. Getting hostname."
                $server = $server.Split('\')[0]
            }
            
            if ($server -notin $processed)
            {
                $null = $processed.Add($server)
                Write-Verbose "Connecting to $server"
            }
            else
            {
                continue
            }
            
            $data = Get-PowerPlan $server
            
            if ($data.Count -gt 1)
            {
                $data.GetEnumerator() | ForEach-Object { $null = $collection.Add($_) }
            }
            else
            {
                $null = $collection.Add($data)
            }
        }
    }
    
    END
    {
        if ($Detailed -eq $true)
        {
            return $collection
        }
        elseif ($processed.Count -gt 1)
        {
            $newcollection = @()
            foreach ($computer in $collection)
            {
                if ($newcollection.Server -contains $computer.Server) { continue }
                                
                $newcollection += [PSCustomObject]@{
                    Server = $computer.Server
                    IsBestPractice = $computer.IsBestPractice
                }
            }
            return $newcollection
        }
        else
        {
            foreach ($computer in $collection)
            {
                return $computer.IsBestPractice
            }
        }
    }
}