functions/Test-DbaTempDbConfiguration.ps1

Function Test-DbaTempDbConfiguration
{
<#
.SYNOPSIS
Evaluates tempdb against several rules to match best practices.
 
.DESCRIPTION
Evaluates tempdb aganst a set of rules to match best practices. The rules are:
TF 1118 enabled - Is Trace Flag 1118 enabled (See KB328551).
File Count - Does the count of data files in tempdb match the number of logical cores, up to 8.
File Growth - Are any files set to have percentage growth, as best practice is all files have an explicit growth value.
File Location - Is tempdb located on the C:\? Best practice says to locate it elsewhere.
File MaxSize Set(optional) - Do any files have a max size value? Max size could cause tempdb problems if it isn't allowed to grow.
 
Other rules can be added at a future date. Only results that don't match best practices will be displayed. To display all results,
use the -Detailed switch.
 
.PARAMETER SqlInstance
The SQL Server instance.You must have sysadmin access and server version must be SQL Server version 2005 or higher.
 
.PARAMETER SqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/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
Switch that allows you to display all test results.
 
.NOTES
Original Author: Michael Fal (@Mike_Fal), http://mikefal.net
Based off of Amit Bannerjee's (@banerjeeamit) Get-TempDB function (https://github.com/amitmsft/SqlOnAzureVM/blob/master/Get-TempdbFiles.ps1)
 
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-DbaTempDbConfiguration
 
.EXAMPLE
Test-DbaTempDbConfiguration -SqlInstance localhost
 
Checks tempdb on the localhost machine.
 
.EXAMPLE
Test-DbaTempDbConfiguration -SqlInstance localhost -Detailed
 
Checks tempdb on the localhost machine. All rest results are shown.
 
#>


    [CmdletBinding()]
    Param (
        [parameter(Mandatory = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [Switch]$Detailed
    )

    BEGIN
    {
        $result = @()
        
    }

    PROCESS
    {
        foreach ($servername in $SqlInstance)
        {
            Write-Verbose "Connecting to $servername"
            $server = Connect-SqlInstance $servername -SqlCredential $SqlCredential

            if ($server.versionMajor -lt 9)
            {
                Write-Warning "This function does not support versions lower than SQL Server 2005 (v9). Skipping server '$servername'."
                continue
            }

            #test for TF 1118
            if ($server.VersionMajor -ge 13)
            {
                $notes = 'SQL 2016 has this functionality enabled by default'
                # DBA May have changed setting. May need to check.
                $value = [PSCustomObject]@{
                    ComputerName = $server.NetName
                    InstanceName = $server.ServiceName
                    SqlInstance = $server.DomainInstanceName
                    Rule = 'TF 1118 Enabled'
                    Recommended = $true
                    CurrentSetting = $true
                }
            }
            else
            {
                $sql = "dbcc traceon (3604);dbcc tracestatus (-1)"
                $tfcheck = $server.Databases['tempdb'].ExecuteWithResults($sql).Tables[0].TraceFlag
                $notes = 'KB328551 describes how TF 1118 can benefit performance.'

                if (($tfcheck -join ',').Contains('1118'))
                {

                    $value = [PSCustomObject]@{
                        ComputerName = $server.NetName
                        InstanceName = $server.ServiceName
                        SqlInstance = $server.DomainInstanceName
                        Rule = 'TF 1118 Enabled'
                        Recommended = $true
                        CurrentSetting = $true
                    }
                }
                else
                {
                    $value = [PSCustomObject]@{
                        ComputerName = $server.NetName
                        InstanceName = $server.ServiceName
                        SqlInstance = $server.DomainInstanceName
                        Rule = 'TF 1118 Enabled'
                        Recommended = $true
                        CurrentSetting = $false
                    }
                }
            }

            if ($value.Recommended -ne $value.CurrentSetting -and $null -ne $value.Recommended)
            {
                $isBestPractice = $false
            }
            else
            {
                $isBestPractice = $true
            }

            $value | Add-Member -Force -MemberType NoteProperty -Name IsBestpractice -Value $isBestPractice
            $value | Add-Member -Force -MemberType NoteProperty -Name Notes -Value $notes
            $result += $value
            Write-Verbose "TF 1118 evaluated"

            #get files and log files
            $datafiles = $server.Databases['tempdb'].ExecuteWithResults("SELECT physical_name as FileName, max_size as MaxSize, CASE WHEN is_percent_growth = 1 THEN 'Percent' ELSE 'KB' END as GrowthType from sys.database_files WHERE type_desc = 'ROWS'").Tables[0]
            $logfiles =  $server.Databases['tempdb'].ExecuteWithResults("SELECT physical_name as FileName, max_size as MaxSize, CASE WHEN is_percent_growth = 1 THEN 'Percent' ELSE 'KB' END as GrowthType from sys.database_files WHERE type_desc = 'LOG'").Tables[0]

            Write-Verbose "TempDB file objects gathered"

            $cores = $server.Processors

            if ($cores -gt 8) { $cores = 8 }

            $value = [PSCustomObject]@{
                ComputerName = $server.NetName
                InstanceName = $server.ServiceName
                SqlInstance = $server.DomainInstanceName
                Rule = 'File Count'
                Recommended = $cores
                CurrentSetting = $datafiles.Rows.Count
            }

            if ($value.Recommended -ne $value.CurrentSetting -and $null -ne $value.Recommended)
            {
                $isBestPractice = $false
            }
            else
            {
                $isBestPractice = $true
            }

            $value | Add-Member -Force -MemberType NoteProperty -Name IsBestpractice -Value $isBestPractice
            $value | Add-Member -Force -MemberType NoteProperty -Name Notes -Value 'Microsoft recommends that the number of tempdb data files is equal to the number of logical cores up to 8.'
            $result += $value

            Write-Verbose "File counts evaluated"

            #test file growth
            $percdata = $datafiles | Where-Object { $_.GrowthType -ne 'KB' } | Measure-Object
            $perclog =  $logfiles  | Where-Object { $_.GrowthType -ne 'KB' } | Measure-Object

            $totalcount = $percdata.count + $perclog.count
            if ($totalcount -gt 0) { $totalcount = $true } else { $totalcount = $false }

            $value = [PSCustomObject]@{
                ComputerName = $server.NetName
                InstanceName = $server.ServiceName
                SqlInstance = $server.DomainInstanceName
                Rule = 'File Growth in Percent'
                Recommended = $false
                CurrentSetting = $totalcount
            }

            if ($value.Recommended -ne $value.CurrentSetting -and $null -ne $value.Recommended)
            {
                $isBestPractice = $false
            }
            else
            {
                $isBestPractice = $true
            }

            $value | Add-Member -Force -MemberType NoteProperty -Name IsBestpractice -Value $isBestPractice
            $value | Add-Member -Force -MemberType NoteProperty -Name Notes -Value 'Set grow with explicit values, not by percent.'
            $result += $value

            Write-Verbose "File growth settings evaluated"
            #test file Location

            $cdata = ($datafiles | Where-Object { $_.FileName -like 'C:*' } | Measure-Object).Count + ($logfiles | Where-Object { $_.FileName -like 'C:*' } | Measure-Object).Count
            if ($cdata -gt 0) { $cdata = $true } else { $cdata = $false }

            $value = [PSCustomObject]@{
                ComputerName = $server.NetName
                InstanceName = $server.ServiceName
                SqlInstance = $server.DomainInstanceName
                Rule = 'File Location'
                Recommended = $false
                CurrentSetting = $cdata
            }

            if ($value.Recommended -ne $value.CurrentSetting -and $null -ne $value.Recommended)
            {
                $isBestPractice = $false
            }
            else
            {
                $isBestPractice = $true
            }

            $value | Add-Member -Force -MemberType NoteProperty -Name IsBestpractice -Value $isBestPractice
            $value | Add-Member -Force -MemberType NoteProperty -Name Notes -Value "Do not place your tempdb files on C:\."
            $result += $value

            Write-Verbose "File locations evaluated"

            #Test growth limits
            $growthlimits = ($datafiles | Where-Object { $_.MaxSize -gt 0 } | Measure-Object).Count + ($logfiles | Where-Object { $_.MaxSize -gt 0 } | Measure-Object).Count
            if ($growthlimits -gt 0) { $growthlimits = $true } else { $growthlimits = $false }

            $value = [PSCustomObject]@{
                ComputerName = $server.NetName
                InstanceName = $server.ServiceName
                SqlInstance = $server.DomainInstanceName
                Rule = 'File MaxSize Set'
                Recommended = $false
                CurrentSetting = $growthlimits
            }

            if ($value.Recommended -ne $value.CurrentSetting -and $null -ne $value.Recommended)
            {
                $isBestPractice = $false
            }
            else
            {
                $isBestPractice = $true
            }

            $value | Add-Member -Force -MemberType NoteProperty -Name IsBestpractice -Value $isBestPractice
            $value | Add-Member -Force -MemberType NoteProperty -Name Notes -Value "Consider setting your tempdb files to unlimited growth."
            $result += $value

            Write-Verbose "MaxSize values evaluated"
        }
    }

    END
    {
        if($Detailed)
        {
            return $result
        }
        else
        {
            $failed = $result | Where-Object { $_.isBestPractice -eq $false }
            if ($null -eq $failed)
            {
                Write-Output "All tests passed! tempdb is properly optimized."
            }
            else
            {
                return $failed
            }
        }
        
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Silent:$false -Alias Test-SqlTempDbConfiguration
    }
}