functions/Set-DbaTempDbConfiguration.ps1

function Set-DbaTempDbConfiguration {
    <#
        .SYNOPSIS
            Sets tempdb data and log files according to best practices.
 
        .DESCRIPTION
            Calculates tempdb size and file configurations based on passed parameters, calculated values, and Microsoft best practices. User must declare SQL Server to be configured and total data file size as mandatory values. Function then calculates the number of data files based on logical cores on the target host and create evenly sized data files based on the total data size declared by the user, with a log file 25% of the total data file size.
             
            Other parameters can adjust the settings as the user desires (such as different file paths, number of data files, and log file size). No functions that shrink or delete data files are performed. If you wish to do this, you will need to resize tempdb so that it is "smaller" than what the function will size it to before running the function.
 
        .NOTES
            Author: Michael Fal (@Mike_Fal), http://mikefal.net
 
            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
 
        .PARAMETER SqlInstance
            The SQL Server Instance to connect to.
         
        .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 DataFileCount
            Specifies the number of data files to create. If this number is not specified, the number of logical cores of the host will be used.
 
        .PARAMETER DataFileSizeMB
            Specifies the total data file size in megabytes. This is distributed across the total number of data files.
 
        .PARAMETER LogFileSizeMB
            Specifies the log file size in megabytes. If not specified, this will be set to 25% of total data file size.
 
        .PARAMETER DataFileGrowthMB
            Specifies the growth amount for the data file(s) in megabytes. The default is 512 MB.
 
        .PARAMETER LogFileGrowthMB
            Specifies the growth amount for the log file in megabytes. The default is 512 MB.
 
        .PARAMETER DataPath
            Specifies the filesystem path in which to create the tempdb data files. If not specified, current tempdb location will be used.
 
        .PARAMETER LogPath
            Specifies the filesystem path in which to create the tempdb log file. If not specified, current tempdb location will be used.
 
        .PARAMETER OutputScriptOnly
            If this switch is enabled, only the T-SQL script to change the tempdb configuration is created and output.
 
        .PARAMETER OutFile
            Specifies the filesystem path into which the generated T-SQL script will be saved.
 
        .PARAMETER DisableGrowth
            If this switch is enabled, the tempdb files will be configured to not grow. This overrides -DataFileGrowthMB and -LogFileGrowthMB.
 
        .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 Silent
            If this switch is enabled, the internal messaging functions will be silenced.
 
        .LINK
            https://dbatools.io/Set-DbaTempDbConfiguration
 
        .EXAMPLE
            Set-DbaTempDbConfiguration -SqlInstance localhost -DataFileSizeMB 1000
 
            Creates tempdb with a number of data files equal to the logical cores where each file is equal to 1000MB divided by the number of logical cores, with a log file of 250MB.
 
        .EXAMPLE
            Set-DbaTempDbConfiguration -SqlInstance localhost -DataFileSizeMB 1000 -DataFileCount 8
 
            Creates tempdb with 8 data files, each one sized at 125MB, with a log file of 250MB.
 
        .EXAMPLE
            Set-DbaTempDbConfiguration -SqlInstance localhost -DataFileSizeMB 1000 -OutputScriptOnly
 
            Provides a SQL script output to configure tempdb according to the passed parameters.
 
        .EXAMPLE
            Set-DbaTempDbConfiguration -SqlInstance localhost -DataFileSizeMB 1000 -DisableGrowth
 
            Disables the growth for the data and log files.
 
        .EXAMPLE
            Set-DbaTempDbConfiguration -SqlInstance localhost -DataFileSizeMB 1000 -OutputScriptOnly
 
            Returns the T-SQL script representing tempdb configuration.
    #>

    [CmdletBinding(SupportsShouldProcess = $true)]
    param (
        [parameter(Mandatory = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter]$SqlInstance,
        [PSCredential]$SqlCredential,
        [int]$DataFileCount,
        [Parameter(Mandatory = $true)]
        [int]$DataFileSizeMB,
        [int]$LogFileSizeMB,
        [int]$DataFileGrowthMB = 512,
        [int]$LogFileGrowthMB = 512,
        [string]$DataPath,
        [string]$LogPath,
        [string]$OutFile,
        [switch]$OutputScriptOnly,
        [switch]$DisableGrowth,
        [switch]$Silent
    )
    begin {
        $sql = @()
        Write-Message -Level Verbose -Message "Connecting to $SqlInstance"
        $server = Connect-SqlInstance $sqlinstance -SqlCredential $SqlCredential
        
        if ($server.VersionMajor -lt 9) {
            Stop-Function -Message "SQL Server 2000 is not supported"
            return
        }
    }
    
    process {
        
        if (Test-FunctionInterrupt) {
            return
        }
        
        $cores = $server.Processors
        if ($cores -gt 8) {
            $cores = 8
        }
        
        #Set DataFileCount if not specified. If specified, check against best practices.
        if (-not $DataFileCount) {
            $DataFileCount = $cores
            Write-Message -Message "Data file count set to number of cores: $DataFileCount" -Level Verbose
        }
        else {
            if ($DataFileCount -gt $cores) {
                Write-Message -Message "Data File Count of $DataFileCount exceeds the Logical Core Count of $cores. This is outside of best practices." -Level Warning
            }
            Write-Message -Message "Data file count set explicitly: $DataFileCount" -Level Verbose
        }
        
        $DataFilesizeSingleMB = $([Math]::Floor($DataFileSizeMB / $DataFileCount))
        Write-Message -Message "Single data file size (MB): $DataFilesizeSingleMB." -Level Verbose
        
        if ($DataPath) {
            if ((Test-DbaSqlPath -SqlInstance $server -Path $DataPath) -eq $false) {
                Stop-Function -Message "$datapath is an invalid path."
                return
            }
        }
        else {
            $Filepath = $server.Databases['tempdb'].ExecuteWithResults('SELECT physical_name as FileName FROM sys.database_files WHERE file_id = 1').Tables[0].Rows[0].FileName
            $DataPath = Split-Path $Filepath
        }
        
        Write-Message -Message "Using data path: $datapath." -Level Verbose
        
        if ($LogPath) {
            if ((Test-DbaSqlPath -SqlInstance $server -Path $LogPath) -eq $false) {
                Stop-Function -Message "$LogPath is an invalid path."
                return
            }
        }
        else {
            $Filepath = $server.Databases['tempdb'].ExecuteWithResults('SELECT physical_name as FileName FROM sys.database_files WHERE file_id = 2').Tables[0].Rows[0].FileName
            $LogPath = Split-Path $Filepath
        }
        Write-Message -Message "Using log path: $LogPath." -Level Verbose
        
        # Check if the file growth needs to be disabled
        if ($DisableGrowth) {
            $DataFileGrowthMB = 0
            $LogFileGrowthMB = 0
        }
        
        $LogSizeMBActual = if (-not $LogFileSizeMB) { $([Math]::Floor($DataFileSizeMB / 4)) }

        # Check current tempdb. Throw an error if current tempdb is larger than config.
        $CurrentFileCount = $server.Databases['tempdb'].ExecuteWithResults('SELECT count(1) as FileCount FROM sys.database_files WHERE type=0').Tables[0].Rows[0].FileCount
        $TooBigCount = $server.Databases['tempdb'].ExecuteWithResults("SELECT TOP 1 (size/128) as Size FROM sys.database_files WHERE size/128 > $DataFilesizeSingleMB AND type = 0").Tables[0].Rows[0].Size
        
        if ($CurrentFileCount -gt $DataFileCount) {
            Stop-Function -Message "Current tempdb not suitable to be reconfigured. The current tempdb has a greater number of files ($CurrentFileCount) than the calculated configuration ($DataFileCount)."
            return
        }
        
        if ($TooBigCount) {
            Stop-Function -Message "Current tempdb not suitable to be reconfigured. The current tempdb ($TooBigCount MB) is larger than the calculated individual file configuration ($DataFilesizeSingleMB MB)."
            return
        }
        
        $EqualCount = $server.Databases['tempdb'].ExecuteWithResults("SELECT count(1) as FileCount FROM sys.database_files WHERE size/128 = $DataFilesizeSingleMB AND type = 0").Tables[0].Rows[0].FileCount
        
        if ($EqualCount -gt 0) {
            Stop-Function -Message "Current tempdb not suitable to be reconfigured. The current tempdb is the same size as the specified DataFileSizeMB."
            return
        }
        
        Write-Message -Message "tempdb configuration validated." -Level Verbose
        
        $DataFiles = $server.Databases['tempdb'].ExecuteWithResults("select f.name as Name, f.physical_name as FileName from sys.filegroups fg join sys.database_files f on fg.data_space_id = f.data_space_id where fg.name = 'PRIMARY' and f.type_desc = 'ROWS'").Tables[0];
        
        #Checks passed, process reconfiguration
        for ($i = 0; $i -lt $DataFileCount; $i++) {
            $File = $DataFiles.Rows[$i]
            if ($File) {
                $Filename = Split-Path $File.FileName -Leaf
                $LogicalName = $File.Name
                $NewPath = "$datapath\$Filename"
                $sql += "ALTER DATABASE tempdb MODIFY FILE(name=$LogicalName,filename='$NewPath',size=$DataFilesizeSingleMB MB,filegrowth=$DataFileGrowthMB);"
            }
            else {
                $NewName = "tempdev$i.ndf"
                $NewPath = "$datapath\$NewName"
                $sql += "ALTER DATABASE tempdb ADD FILE(name=tempdev$i,filename='$NewPath',size=$DataFilesizeSingleMB MB,filegrowth=$DataFileGrowthMB);"
            }
        }
        
        if (-not $LogFileSizeMB) {
            $LogFileSizeMB = [Math]::Floor($DataFileSizeMB / 4)
        }
        
        $logfile = $server.Databases['tempdb'].ExecuteWithResults("SELECT name, physical_name as FileName FROM sys.database_files WHERE file_id = 2").Tables[0].Rows[0];
        $Filename = Split-Path $logfile.FileName -Leaf
        $LogicalName = $logfile.Name
        $NewPath = "$LogPath\$Filename"
        $sql += "ALTER DATABASE tempdb MODIFY FILE(name=$LogicalName,filename='$NewPath',size=$LogFileSizeMB MB,filegrowth=$LogFileGrowthMB);"
        
        Write-Message -Message "SQL Statement to resize tempdb." -Level Verbose
        Write-Message -Message ($sql -join "`n`n") -Level Verbose
        
        if ($OutputScriptOnly) {
            return $sql
        }
        elseif ($OutFile) {
            $sql | Set-Content -Path $OutFile
        }
        else {
            if ($Pscmdlet.ShouldProcess($SqlInstance, "Executing query and informing that a restart is required.")) {
                try {
                    $server.Databases['master'].ExecuteNonQuery($sql)
                    Write-Message -Level Verbose -Message "tempdb successfully reconfigured."
                    
                    [PSCustomObject]@{
                        ComputerName         = $server.NetName
                        InstanceName         = $server.ServiceName
                        SqlInstance          = $server.DomainInstanceName
                        DataFileCount        = $DataFileCount
                        DataFileSizeMB       = $DataFileSizeMB
                        SingleDataFileSizeMB = $DataFilesizeSingleMB
                        LogSizeMB            = $LogSizeMBActual
                        DataPath             = $DataPath
                        LogPath              = $LogPath
                        DataFileGrowthMB     = $DataFileGrowthMB
                        LogFileGrowthMB      = $LogFileGrowthMB
                    }
                    
                    Write-Message -Level Output -Message "tempdb reconfigured. You must restart the SQL Service for settings to take effect."
                }
                catch {
                    # write-exception writes the full exception to file
                    Stop-Function -Message "Unable to reconfigure tempdb. Exception: $_" -Target $sql -InnerErrorRecord $_
                    return
                }
            }
        }
    }
    end { 
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Silent:$false -Alias Set-SqlTempDbConfiguration
    }
}