Set-SqlDefaultPath.ps1

Set-SqlDefaultPath.ps1

function Set-SqlDefaultPath {
    param (
        [Parameter(Mandatory=$true)][string]$SqlInstance,
        $NewDefaultDataPath = "",
        $NewDefaultLogPath = "",
        $NewDefaultBackupPath = ""
    )
    try {
        import-module dbatools
    }
    catch {
        Write-Error "Failed to import dbatools (required): www.dbatools.io"
    }

    # The following SQL is copied from a combination of Thomas LeRock and MsSqlTips:
    # https://thomaslarock.com/2017/06/changing-default-database-file-locations-in-sql-server-2016/
    # https://www.mssqltips.com/sqlservertip/1583/changing-the-default-sql-server-backup-folder/
    $setDefaultDataPathSql = @"        
        EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE'
            , N'Software\Microsoft\MSSQLServer\MSSQLServer'
            , N'DefaultData'
            , REG_SZ
            , N'$NewDefaultDataPath'
        GO
"@

    $setDefaultLogPathSql = @"
        EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE'
            , N'Software\Microsoft\MSSQLServer\MSSQLServer'
            , N'DefaultLog'
            , REG_SZ
            , N'$NewDefaultLogPath'
        GO
"@

    $setDefaultBackupPathSql = @"
        EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE'
            , N'SOFTWARE\Microsoft\MSSQLServer\MSSQLServer'
            , N'BackupDirectory'
            , REG_SZ
            , N'$NewDefaultBackupPath'
"@

    if ($NewDefaultDataPath -notlike ""){
        Invoke-DbaQuery -SqlInstance $SqlInstance -Query $setDefaultDataPathSql
    }
    if ($NewDefaultLogPath -notlike ""){
        Invoke-DbaQuery -SqlInstance $SqlInstance -Query $setDefaultLogPathSql
    }
    if ($NewDefaultBackupPath -notlike ""){
        Invoke-DbaQuery -SqlInstance $SqlInstance -Query $setDefaultBackupPathSql
    }

    return "Restart required"
}

<#

Tutorial part 1:
Get the current default paths by running the following (requires dbatools)

    Get-DbaDefaultPath  $SqlInstance

Tutorial part 2:
Change the default paths using the following. (Note, updating the data path sometimes updates the log path too, not sure why):

    $SqlInstance = "localhost"
    $NewDefaultDataPath = ""
    $NewDefaultLogPath = ""
    $NewDefaultBackupPath = ""

    Set-SqlDefaultPath -SqlInstance $SqlInstance -NewDefaultDataPath $NewDefaultDataPath -NewDefaultLogPath $NewDefaultLogPath -NewDefaultBackupPath $NewDefaultBackupPath 

Tutorial part 3:
Repeat tutorial part 1. Observe there has been no change to the default paths. Then restart the SQL Server instance and check the paths again. They should now have updated.

Note: Existing database files will not be moved to the new paths. These changes will only take effect for new databases.

#>