In our careers we tend to hit a lot of first times. Tonight was no different. I undertook my first in-place upgrade of SQL Server 2008 to SQL Server 2008 R2. Traditionally I have never opted for performing these types of upgrades as they limit your ability to rollback easily in the case of any issues. Having said that I understand and agree that sometimes there is no other option to take due to the environment that you are working in. my preferred options would be a side by side installation or a new build on new hardware.
Like anything when it comes to SQL Server, you need to plan your approach and test what you are going to do and this can minimize not eliminate the possible upgrade complications. Put together your implementation plan and then work through it in your development and test environments to ensure that you have ironed out any of the possible issues before heading to production.
A few things that you should look at doing before starting your in-place upgrade:
Just like any other SQL Server 2008 R2 installation, you kick it off by executing the setup.exe for SQL Server Installation Center. On the Installation tab you need to select “Upgrade from SQL Server 2000, SQL Server 2005 or SQL Server 2008”, Follow the prompts in the GUI and your in-place upgrade is nearly complete. As long as your Installation completes without any errors, your next step is to install any new features that you may want that you did not have in your old version of SQL Server. If there are no other features that you need to install, or the installation of the new features completes successfully, you are now ready to install Service Pack 1 for SQL Server 2008 R2.
It is now time to confirm that your instance is working and there are no errors or issues in your SQL Errorlog. As long as there is no issues then to finish off your environment to make it ready for your users to connect undertake the following:
Run DBCC CheckDB
Backup all database