functions/Get-DbaDatabaseSpace.ps1

function Get-DbaDatabaseSpace {
    <#
        .SYNOPSIS
            Returns database file space information for database files on a SQL instance.
 
        .DESCRIPTION
            This function returns database file space information for a SQL Instance or group of SQL Instances. Information is based on a query against sys.database_files and the FILEPROPERTY function to query and return information.
 
            File free space script borrowed and modified from Glenn Berry's DMV scripts (http://www.sqlskills.com/blogs/glenn/category/dmv-queries/)
 
        .PARAMETER SqlInstance
            Specifies the SQL Server instance(s) to scan.
 
        .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 Database
            Specifies the database(s) to process. Options for this list are auto-populated from the server. If unspecified, all databases will be processed.
 
        .PARAMETER ExcludeDatabase
            Specifies the database(s) to exclude from processing. Options for this list are auto-populated from the server.
 
        .PARAMETER IncludeSystemDBs
            If this switch is enabled, system databases will be processed. By default, only user databases are processed.
 
        .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.
 
        .EXAMPLE
            Get-DbaDatabaseSpace -SqlInstance localhost
 
            Returns all user database files and free space information for the localhost.
 
        .EXAMPLE
            Get-DbaDatabaseSpace -SqlInstance localhost | Where-Object {$_.PercentUsed -gt 80}
 
            Returns all user database files and free space information for the local host. Filters the output object by any files that have a percent used of greater than 80%.
 
        .EXAMPLE
            'localhost','localhost\namedinstance' | Get-DbaDatabaseSpace
 
            Returns all user database files and free space information for the localhost and localhost\namedinstance SQL Server instances. Processes data via the pipeline.
 
        .EXAMPLE
            Get-DbaDatabaseSpace -SqlInstance localhost -Database db1, db2
 
            Returns database files and free space information for the db1 and db2 on localhost.
 
        .NOTES
            Author: Michael Fal (@Mike_Fal), http://mikefal.net
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: MIT https://opensource.org/licenses/MIT
 
        .LINK
            https://dbatools.io/Get-DbaDatabaseSpace
    #>

    [CmdletBinding()]
    param ([parameter(ValueFromPipeline, Mandatory = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [System.Management.Automation.PSCredential]$SqlCredential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [switch]$IncludeSystemDBs,
        [switch][Alias('Silent')]$EnableException
    )

    begin {
        Write-Message -Level System -Message "Bound parameters: $($PSBoundParameters.Keys -join ", ")."

        $sql = "SELECT SERVERPROPERTY('MachineName') AS ComputerName,
                                   ISNULL(SERVERPROPERTY('InstanceName'), 'MSSQLSERVER') AS InstanceName,
                                   SERVERPROPERTY('ServerName') AS SqlInstance,
                    DB_NAME() as DBName
                    ,f.name AS [FileName]
                    ,fg.name AS [Filegroup]
                    ,f.physical_name AS [PhysicalName]
                    ,f.type_desc AS [FileType]
                    ,CAST(CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int)/128.0 AS FLOAT) as [UsedSpaceMB]
                    ,CAST(f.size/128.0 - CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int)/128.0 AS FLOAT) AS [FreeSpaceMB]
                    ,CAST((f.size/128.0) AS FLOAT) AS [FileSizeMB]
                    ,CAST((FILEPROPERTY(f.name, 'SpaceUsed')/(f.size/1.0)) * 100 as FLOAT) as [PercentUsed]
                    ,CAST((f.growth/128.0) AS FLOAT) AS [GrowthMB]
                    ,CASE is_percent_growth WHEN 1 THEN 'pct' WHEN 0 THEN 'MB' ELSE 'Unknown' END AS [GrowthType]
                    ,CASE f.max_size WHEN -1 THEN 2147483648. ELSE CAST((f.max_size/128.0) AS FLOAT) END AS [MaxSizeMB]
                    ,CAST((f.size/128.0) AS FLOAT) - CAST(CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int)/128.0 AS FLOAT) AS [SpaceBeforeAutoGrow]
                    ,CASE f.max_size WHEN (-1)
                                        THEN CAST(((2147483648.) - CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int))/128.0 AS FLOAT)
                                        ELSE CAST((f.max_size - CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int))/128.0 AS FLOAT)
                                        END AS [SpaceBeforeMax]
                    ,CASE f.growth WHEN 0 THEN 0.00
                                    ELSE CASE f.is_percent_growth WHEN 0
                                                    THEN CASE f.max_size
                                                            WHEN (-1)
                                                            THEN CAST(((((2147483648.)-f.Size)/f.Growth)*f.Growth)/128.0 AS FLOAT)
                                                            ELSE CAST((((f.max_size-f.Size)/f.Growth)*f.Growth)/128.0 AS FLOAT)
                                                            END
                                                    WHEN 1
                                                    THEN CASE f.max_size
                                                            WHEN (-1)
                                                            THEN CAST(CONVERT([int],f.Size*power((1)+CONVERT([float],f.Growth)/(100),CONVERT([int],log10(CONVERT([float],(2147483648.))/CONVERT([float],f.Size))/log10((1)+CONVERT([float],f.Growth)/(100)))))/128.0 AS FLOAT)
                                                            ELSE CAST(CONVERT([int],f.Size*power((1)+CONVERT([float],f.Growth)/(100),CONVERT([int],log10(CONVERT([float],f.Max_Size)/CONVERT([float],f.Size))/log10((1)+CONVERT([float],f.Growth)/(100)))))/128.0 AS FLOAT)
                                                            END
                                                    ELSE (0)
                                                    END
                                    END AS [PossibleAutoGrowthMB]
                    , CASE f.max_size WHEN -1 THEN 0
                                        ELSE CASE f.growth
                                                WHEN 0 THEN (f.max_size - f.size)/128
                                                ELSE CASE f.is_percent_growth
                                                        WHEN 0
                                                        THEN CAST((f.max_size - f.size - ( CONVERT(FLOAT,FLOOR((f.max_size-f.Size)/f.Growth)*f.Growth)))/128.0 AS FLOAT)
                                                        ELSE CAST((f.max_size - f.size - ( CONVERT([int],f.Size*power((1)+CONVERT([float],f.Growth)/(100),CONVERT([int],log10(CONVERT([float],f.Max_Size)/CONVERT([float],f.Size))/log10((1)+CONVERT([float],f.Growth)/(100)))))))/128.0 AS FLOAT)
                                                        END
                                                END
                                    END AS [UnusableSpaceMB]
 
                FROM sys.database_files AS f WITH (NOLOCK)
                LEFT OUTER JOIN sys.filegroups AS fg WITH (NOLOCK)
                ON f.data_space_id = fg.data_space_id"

    }

    process {
        foreach ($instance in $SqlInstance) {
            try {
                Write-Message -Level VeryVerbose -Message "Connecting to $instance." -Target $instance
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            }
            catch {
                Stop-Function -Message "Failed to process Instance $Instance." -ErrorRecord $_ -Target $instance -Continue
            }

            if ($server.VersionMajor -lt 9) {
                Write-Message -Level Warning -Message "SQL Server 2000 not supported. $server skipped."
                continue
            }

            #If IncludeSystemDBs is true, include systemdbs
            #look at all databases, online/offline/accessible/inaccessible and tell user if a db can't be queried.
            try {
                if (Test-Bound "Database") {
                    $dbs = $server.Databases | Where-Object Name -In $Database
                }
                elseif ($IncludeSystemDBs) {
                    $dbs = $server.Databases | Where-Object IsAccessible
                }
                else {
                    $dbs = $server.Databases | Where-Object { $_.IsAccessible -and $_.IsSystemObject -eq 0 }
                }

                if (Test-Bound "ExcludeDatabase") {
                    $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase
                }
            }
            catch {
                Stop-Function -Message "Unable to gather databases for $instance." -ErrorRecord $_ -Continue
            }

            foreach ($db in $dbs) {
                try {
                    Write-Message -Level Verbose -Message "Querying $instance - $db."
                    If ($db.status -ne 'Normal' -or $db.IsAccessible -eq $false) {
                        Write-Message -Level Warning -Message "$db is not accessible." -Target $db
                        continue
                    }
                    #Execute query against individual database and add to output
                    foreach ($row in ($db.ExecuteWithResults($sql)).Tables.Rows) {
                        if ($row.UsedSpaceMB -is [System.DBNull]) {
                            $UsedMB = 0
                        }
                        else {
                            $UsedMB = [Math]::Round($row.UsedSpaceMB)
                        }
                        if ($row.FreeSpaceMB -is [System.DBNull]) {
                            $FreeMB = 0
                        }
                        else {
                            $FreeMB = [Math]::Round($row.FreeSpaceMB)
                        }
                        if ($row.PercentUsed -is [System.DBNull]) {
                            $PercentUsed = 0
                        }
                        else {
                            $PercentUsed = [Math]::Round($row.PercentUsed)
                        }
                        if ($row.SpaceBeforeMax -is [System.DBNull]) {
                            $SpaceUntilMax = 0
                        }
                        else {
                            $SpaceUntilMax = [Math]::Round($row.SpaceBeforeMax)
                        }
                        if ($row.UnusableSpaceMB -is [System.DBNull]) {
                            $UnusableSpace = 0
                        }
                        else {
                            $UnusableSpace = [Math]::Round($row.UnusableSpaceMB)
                        }

                        [pscustomobject]@{
                            ComputerName         = $server.NetName
                            InstanceName         = $server.ServiceName
                            SqlInstance          = $server.DomainInstanceName
                            Database             = $row.DBName
                            FileName             = $row.FileName
                            FileGroup            = $row.FileGroup
                            PhysicalName         = $row.PhysicalName
                            FileType             = $row.FileType
                            UsedSpaceMB          = $UsedMB
                            FreeSpaceMB          = $FreeMB
                            FileSizeMB           = $row.FileSizeMB
                            PercentUsed          = $PercentUsed
                            AutoGrowth           = $row.GrowthMB
                            AutoGrowType         = $row.GrowthType
                            SpaceUntilMaxSizeMB  = $SpaceUntilMax
                            AutoGrowthPossibleMB = $row.PossibleAutoGrowthMB
                            UnusableSpaceMB      = $UnusableSpace
                        }
                    }
                }
                catch {
                    Stop-Function -Message "Unable to query $instance - $db." -Target $db -ErrorRecord $_ -Continue
                }
            }
        }
    }

    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Alias Get-DbaDatabaseFreeSpace
    }
}