I have been using SQL Server 2008 R2 for quite a while, and it is working great. Now I need to use SQL Server 2012. Will this effect my existing databases? How much risk is involved in installing SQL Server 2012 on a machine that has SQL Server 2008 R2 running?


2 Answers 2


You can simply install a new, named instance, and the two instances can live side-by-side with no risk - just be sure that your connections strings etc. are clear and correct (many problems arise from connecting to LOCALHOST when you meant to connect to LOCALHOST\OtherInstance).

Depending on resources you may want to be sure to cap both servers using the max server memory configuration option, or perhaps even only running one instance at a time. I assume this is on your local development environment.

I'd suggest abandoning the 2008 R2 version of the client tools and using the 2012 version consistently. It has much better functionality and can manage both versions seamlessly.

  • 6
    +1 Here's also a lot of great considerations for side-by-side instances, and depending on what the major and minor versions it'll point out shared items and possible contention. SQL Server 2012 isn't mentioned, but the ideas remain the same: technet.microsoft.com/en-us/library/ee210714(v=SQL.105).aspx Jun 5, 2013 at 12:35
  • @ThomasStringer good point. We had a lot of issues with 2005/2008 side by side using shared features.
    – Cougar9000
    Jun 5, 2013 at 14:59
  • Aaron Bertrand Thank you so much. We haved an 2008 instance and a 2012 instance, but we were messing up the connections so we were actually working on 2008 but thiking we were in 2012. We didn't know about the instances name, but thanks to your answer we solve it. Thank you!
    – Atemi
    Apr 23, 2014 at 14:52

Generally yes. Your services on 2008 R2 will continue running normally unless you manually make some changes.

Only impact that sql 2012 can have is if you plan to run some performance intensive operations but nothing else apart from that.

Here is a good article on MSDN on site-by-side support for different versions of SQL Server http://msdn.microsoft.com/en-us/library/ms143694.aspx

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