There isn't much information around (other than the readme for service packs) on which are the best practices on installing Service Packs, Cumulative Updates, Hotfixes on SQL Server installation.

...well till today really :-)

This is nothing official from Microsoft but still the following are the best practices recommended from my PFE colleague Uttam (which has kindly agreed for me to copy in my blog without any copyright request :) - Txs Uttam) .

 Best practices for installing service packs, cumulative updates and hotfixes for SQL Server

1. Test on a test/dev SQL Server first and only after you have confirmed that all applications are working as expected then install it on a production SQL Server.
2. Review the Readme for Service Pack/cumulative update/hotfix. Any concerns/recommendations will be found in the readme.
3. Run DBCC CHECKDB on ALL databases (user and system databases) and ensure that there were no errors reported.
4. Backup ALL databases (user and system databases) and full-text catalogs (if applicable). This is NOT required but highly recommended.
5. Stop Monitoring and Anti-virus services
6. Make sure you have the proper permissions to install (administrative privilege on server/cluster node)
7. The below points are for clustered SQL Server instance
• Make sure ALL SQL resources come online on ALL cluster nodes
• Make sure that ALL disk resources (even the ones that not being used by SQL Server) are online and not in failed state.
• Verify that there are no dependencies other than those created by the SQL Server setup on any SQL Server cluster resources.
• Run MPSRPT_SQL.exe on all cluster nodes (not required but recommended)
• Make sure all remote desktop connections are closed. You can connect to the node (you are running the setup from) using remote desktop connections but you should disconnect any remote connections to other cluster nodes.

- Beatrice Nicolini & the real contributor :-) - Uttam Parui -