In discussion with Microsoft OS support escalation engineers during a SQLServerFAQ (the original link was to the meeting blog entry which has since disappeared) meeting one of them revealed that the most common issue that is raised with them is when a system rolls or refused to install back a service pack or patch or hotfix.

So why do some systems stubbornly refuse to upgrade or accept service packs? If at some time in the past the system drive became full and a well meaning engineer cleared off "unused" or old files then, this could be the smoking gun. The major reason for service packs failing or rolling back was the deletion or loss of MSP files. And a frequent cause of their deletion was freeing space on full system drives. A missing MSP file will cause subsequent patches which refer to this file to fail and roll back. It is difficult to copy these files from other systems as they are given a GUID name when when are created by the msi install process. The most straight forward solution is a complete reinstall. So the moral is: don't delete or let anyone delete *.msp files! They don't stop your system working but they do stop upgrades!

Fundamental to the use of any agency software is the ability to recover from a loss of the main computer where the agency's data is stored. Disaster recovery or DR as it is known looks a methods to maintain high availability when part of the core process fails.  

Yesterday the was a meeting of DBAs at the Microsoft UK HQ (Thames Valley Park, Reading). This was held under the banner of Tony Rogerson's SQL Server FAQ user group. There were presentations given by Clive Challinor, SQL Core Escalation engineer and Daniel Sol SQL Server Technical Support engineer. In many respects the presentations were made at a high technical level, while still being an overview of some of the issues, mainly commonly held misconceptions, concerning memory and page file usage in SQL 2008.
At the other end of the scale, I gave a brief overview of a product which was news to quite a few present. One of the deficiencies of the Express edition of MS SQL 2008 is the lack of an easy to use backup scheduler. SQLBackupAndFTP is an excellent little application that nicely (in the true sense of the word) fills the void in SQL Express 2008 functionality.
Tony Rogerson, SQL Server MVP then gave a good overview of Building a Resilient Environment - Backups/Restore; Log Shipping and Mirroring. Tony looked at the basics an environment needs in order to be able to recover from problems be they an administrator dropping tables accidentally, users deleting data, corruption etc applicable for SQL Express through to Enterprise editions. What is available and how to set it up and how it works, the concepts, point in time recovery, Log Shipping fundamentals and Mirroring Fundamentals.