I would like to upgrade two Windows Server 2008 servers to Window Server 2008R2 and would like to know if anyone else has done this and if they ran into any issues. I am running Hyper V on both of these servers, I dont' know if that complicates things or not.
I'm upgrading my Hyper-V/2008 machine tonight. Only 2 issues that I've had is that I needed to move the page file off of the system drive to allow for enough free space, and I decided to discard my snapshots from my VMs before doing the upgrade.
These KB articles were helpful for me...
What kind of services do you use this Win2008 server for? Is it just a virtualization platform? If so, then I would suggest not upgrading but rather deploy R2 on new hardware, test it in a lab and make sure it works as you expect, then migrate the virtual machines from the old box to the new box in a properly staged go-live strategy.
In general, I try and avoid in place OS upgrades for anything other than test machines. It's always better to start from scratch.