The tldr; is at the bottom, after the story mode writeup. Feel free to CTRL+END or hyper-scroll your way there, or read the machinations of my troubleshooting on your way there.
This is an old project of mine and goes back to 2009. It's not the first time I used virtualization, but it was the first time I'd really delved into Hyper-V and, to be fair, Hyper-V had only recently become GA and was new, basic, but functional.
I had started working at an M&A firm in 2005 and I'd stuck around even though the organization has started going through a lot of changes and reductions. Entire departments were being downsized and let go and even the IT Department was being dramatically reduced. Remarkably, I was the last man standing in IT at the end in 2012 and I'd even picked up a lot of Facilities responsibilities by then.
In 2009 we'd gone through a rebrand in between some of the RIFs. It was partially due to the mother company also rebranding in order to drop a 3-letter moniker that we'd also had, and the new name allowed us to more closely align with them even though we had vastly different businesses. We were M&A while they were one of the big 4 tax/audit/advisory firms.
Anyway, there was a lot of...uh..."aging" server infrastructure that I inherited which had service contracts coming up for renewal. Approximately $50,000 worth, which was a LOT of money for a getting-small-by-the-year firm and, quite frankly, there were about 20-odd servers that I had to manage which took up a lot of time. And the reboots. Oh, God, the reboots. They took so long. Patching was a nightmare.
There were 2 main options:
Keep doing the same and pay for a lot of support on hardware that would probably start failing in the next year or 2
Consolidate some of the hardware with virtualization
I decided on the latter.
Now this firm had used some of VMWare's earlier products so that the Software Development team could test their code in different environments, but we'd never used a hypervisor for servers before.
Taking into account our ongoing revenue deficiency I'd decided to give Hyper-V a shot. It was new, free and in testing seemed to be...fine? The biggest question I had was how do I take an existing server and turn it into a VM? I really do not remember now how I stumbled on Sysinternals Disk2VHD, but that's what I used and it worked flawlessly.
So with that tool having been tested on a couple of desktops I turned my eye to which servers I would virtualize, and which servers I would convert to hypervisors. Full disclaimer, I would NOT be dual-purposing servers now like I did back then, but I had little guidance, little experience and no network back then to reach out to. This is not to say that there were any issues with it, I just wanted to be clear that I wouldn't mix-use a hypervisor today.
There were 2 newer servers we had which I knew would be the bet options for converting to hypervisors: a Dell PowerEdge R710 & an R610. They had newer, multicore CPUs and were able to accommodate a lot more RAM than the older PowerEdge 1950s & similar generation servers we had (I apologize for not remember all the models from 20 years ago).
The R610 was a domain controller and I do not recall what role the R710 was performing, but both had several open slots for additional hard drives, RAM and 1 empty CPU socket, so I got to work putting a shopping list together and wrote up the final plan for approval by the CFO.
The plan was approved, likely because the hardware upgrades would only cost a few thousand dollars vs. the 50,000 continuing support on a lot of the older servers would. Plus, the CFO had a lot of faith in me as I'd been accepting more and more responsibility for a few years while the department I'd been working for was reduced to only me.
So I scheduled an extended downtime and got to work. First up: make sure those hardware upgrades worked.
As I was adding additional disks to the servers I created new RAID disks as I didn't want to scrap the functions of the existing servers. I'd like to think that I chose RAID10, but it might have been RAID5; I really do not recall now. Once they were booted back up I installed Hyper-V. Both servers were running Windows Server 2008 (this was pre-R2). Once rebooted, I used the Disk2VHD tool and an external, USB hard drive to start capturing the older servers.
Really, there's not a lot to write about for this process. It was straightforward and worked perfectly. It just took a long time to finish as we're talking about USB2 days.
There were a few stability-related issues that came up occasionally, but it was pretty rare. Upgrading to 2008R2 fixed those, and I'd write those issues off as platform maturity issues. I think they caused a total of 3 reboots over 4 months.
This project opened my eyes to a different way of building server infrastructure as previously the standard was 1 service per server, but with the hardware performance changes that had started occurring and the maturity of Type1 hypervisors multiple racks could be easily replaced with 1 or 2 racks, and I've never considered NOT virtualizing servers since then, except for rare, specific cases where virtualization was specifically not supported by a vendor.
tldr; saved a ton of money by converting existing, old servers to virtual using Hyper-V.
Total cost: I'm not sure, but probably $2-3,000.