Brent Ozar has a take:
Sandra Delany (LinkedIn) wrote a well-thought-out blog post called, “Should a SQL Server DBA Know Windows Clustering?” She’s got about 20 years of DBA experience, and she works for Straight Path (a firm I respect) as a consultant. You can probably guess based on her background that yes, she believes you should know how to set up, configure, and troubleshoot Windows clustering. It’s a good post, and you should read it.
But… I don’t agree.
Read on for Brent’s opinion. I do agree that there are companies that don’t need high availability, and that there are plenty of problems you can run into if you don’t understand how it all works. I also think that, if you’re a DBA responsible for maintaining servers, and your company isn’t using any kind of high availability option, it’s important at least to learn how the mechanisms work so that, if HA does become important, you aren’t pushing back because of ignorance in the product.
But on the flip side, where does that rank in importance? It’s probably closer to the middle (or lower) than the top of the list. And I definitely agree that disaster recovery is generally the more important of the two if you can only have one. But even there, we have exceptions in things like stock trading systems or data warehouses, where you can rebuild the system from external sources.