When you have 8000+ databases on an instance, this is a huge deal. You’re looking at over two and a half hours just to bring SQL Server online after installing an SP or CU. While the instance is in script update mode, incoming connections are locked down and the service remains in the Starting status. Only the Dedicated Administrator Connection can be used to connect to the instance remotely.
Taking advantage of having a Failover Cluster Instance to patch the passive node in advance is great for minimizing downtime for Windows updates. But whether you have an FCI or not, SQL Server will remain in the “Starting” state until all of your databases have been through this process after installing an update. What was once a 10-minute failover is now a multi-hour ordeal, and maintenance windows become a lot harder to negotiate.
Andy’s pretty far over on the right-hand side of that Bell curve, but I like his SQL Server suggestion because even with just a few hundred or a couple thousand databases, you’re still talking real time savings.