Virtualization with Kevin and Brent

I work with some of the most knowledgeable VMWare admins in Nashville, and we have top of the line hardware for the VM servers, including EMC Symmetrix DMX's hosting their disk partitions. Even given that investment in hardware and training, I still would not put a production instance of SS2k5 on a VM. So far, I have not been able to get the same level of performance that I would get from physical hardware. (I think you'd agree that I have enough experience and knowledge to do it if it were possible.) I think most of the trend towards virtualizing SS comes from developers wanting their apps to run on dedicated instances. Rather than proliferating dozens of dedicated, single-app instances, I have instead consolidated down to a handful of clustered servers. This methodology also saves money by decreasing the number of OS and SS licenses needed and by amortizing the cost of the hardware across more applications. For hardware expansion, we're looking at using blade servers as cluster nodes because they have similar advantages to VMs without the drawbacks of virtualized hardware. I'm going to be looking into how well SS2k8 runs on a VM this summer, but for now my opinion is that production instances belong on physical servers.

I agree with Morris.  I am trying to consolidate SQL Server instances onto good hardware, move web sites and applications onto VMs on the old database servers, and get rid of all the 1u and 2u units in our data center (where our biggest overage in terms of cost is not bandwidth or services but rather power and HVAC).  I think if we do it right we will be able to remove an entire rack with no noticeable impact to users, since almost all of the 1u and 2u servers are at minimal capacity.  Now if I could only get rid of the Linux rack used by one of our vendors...

If you are looking for database performance, VMs are the wrong place to look. VMs are great if a database doesn't require a whole box and can't share an instance with others (for whatever reason).