Moving system databases. Whenever I have brought this up with a co-worker they seem to get a bit freaked out and want to avoid moving them.  I used to be the same, but happily now I am comfortable moving them around.

Let me first tell you why I want to move them.  I like to have my Data files on the D: drive, Log files on the E: drive, Backup files on the F: and my Tempdb files on the G: Drive.  These are all SAN drives.  This method keeps me consistent for all my servers and I am able to quickly know where to find everything I need.  I am also able to easily identify which drive my problem is on.  But my favorite reason is that in the past (three separate times), I have lost the OS to my SQL Server.  Because I had master, model, and msdb on the D: drive, after a quick re-install of SQL and the correct patch, I was able to re-point to master and everything came up beautifully without further recovery.  I had over 70 databases on one of these instances, and this method prevented me from having to restore each one along with log files. It was a wonderful surprise the first time it worked.

There are performance reasons for splitting out your files on to different drives, but we can get into that later because it requires its own post.

This step comes before I split out my tempdb files, so I am only moving one. You could easily add more lines of code to allow you to move more tempdb files.

So let’s get to the code and you will see how easy it is to do.  You will never fear moving the system databases again. This code is set up for SQL2008, but is easily modified for whatever version you are using.  Just set it up to match the folder structure.

--Check to see where your files are now.

SELECT *
FROM sys.master_files

--Move your files
USE master
GO

ALTER DATABASE model
MODIFY FILE (NAME = modeldev, FILENAME = 'D:\MSSQL10.MSSQLSERVER\MSSQL\DATA\model.mdf');
GO

ALTER DATABASE model
MODIFY FILE (NAME = modellog, FILENAME = 'E:\MSSQL10.MSSQLSERVER\MSSQL\DATA\modellog.ldf');
GO

ALTER DATABASE msdb
MODIFY FILE (NAME = MSDBData, FILENAME = 'D:\MSSQL10.MSSQLSERVER\MSSQL\DATA\MSDBData.mdf');
GO

ALTER DATABASE msdb
MODIFY FILE (NAME = MSDBLog, FILENAME = 'E:\MSSQL10.MSSQLSERVER\MSSQL\DATA\MSDBLog.ldf');
GO

ALTER DATABASE  tempdb
MODIFY FILE (NAME = tempdev, FILENAME = 'G:\MSSQL10.MSSQLSERVER\MSSQL\DATA\tempdb.mdf');
GO

ALTER DATABASE tempdb
MODIFY FILE (NAME = templog, FILENAME = 'G:\MSSQL10.MSSQLSERVER\MSSQL\DATA\templog.ldf');
GO

Stop the SQL Server and physically copy over the files. Restart the SQL Server and verify they moved your files moved.

SELECT *
FROM sys.master_files

Now here is the next part of the magic.  Go to the SQL Server Configuration Manager, right click on your SQL Server and go to Advanced.  There is a line for Start-up Parameters.  You will also need to modify this string to match your version, but I simply paste this in:

-dD:\MSSQL10.MSSQLSERVER\MSSQL\DATA\master.mdf;-eC:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\Log\ERRORLOG;-lE:\MSSQL10.MSSQLSERVER\MSSQL\DATA\mastlog.ldf

Then I stop my SQL Server, copy my master files to the right locations and start up SQL Server again.  It is so easy.  Test it out a few times until you are comfortable and then it will be like you are moving them around with a magic wand.