Perfomance of SQL Server on Hyper-V VM

Question

I decided to try server virtualization and I have not had such an experience before. I installed Hyper-V Core 2012, created a virtual machine and installed Windows Server 2008. On this VM I should install MS SQL Server 2008 R2. Should I place database files inside this VM or just on Hyper-V Server? My colleagues believe that the performance of SQL Server will be low if VM will contain database files.

Answer 1

How long is a piece of string?

Generally:

• Hyper-V is slower than bare metal, but just a couple of percent.
• The critical point pretty much always is IO. For SQL Server also.
• Hyper-V will not magically fix a bad disc layout.

I run a high performance SQL Server happily on Hyper-V, but it has 10 SSD and some HD attached ONLY to it (via pass through) to handle the IO load.

All normal standard well known best practices apply (and if you do not know them, learn your job as professional admin).

The general opinion SQL Servers are slow in Hyper-V comes from people not thinking. They put Hyper-V on a machine, add a slow disc subsystem, then run all VMS on it. The result is abysmal performance. And then they blame Hyper-V for their own bad planning. Want SQL performance? Make sure you have the IO budget. And Hyper-V does not change anything.