Do you have any idea how noisy a server is? It's unbearable unless you dedicate a room for it, or a small closet, but then you'll need climatisation and so on. Also,why do you think you need Xen? Unless this is for a medium company, it doesn't make sense for home use.
Yes, I do know how noisy servers are. I have some, they take energy, put out noise, and do things. I still want a good one.
Went myself to the same path, Xen, then KVM, then realized that an Ubuntu LTS with ZFS for daily use is more than enough, requires zero maintenance, and can still do virtualization.
Virtualization is very cumbersome to setup, both in hardware and in software, video passthrough is almost impossible to set and maintain, and the whole mess is NOT hack-proof, anyway, if that is what you want to achieve. Nothing is hack proof.
As for Xen, I have a good idea of what I'm getting myself into, and I have a long and successful history of maintaining complicated and intricate systems. My current solution is a Xeon X5650 running FreeBSD , but I have outgrown this considerably. I'm also going to be sharing this server with other people, who will be running their own software and operating systems, which is why I want Xen.
What do you need a 48 core server for? If this is a hosting operation, do you have a 10Gb/s internet feed to go along with it? I would first look into whether a massive server is really needed or if a 8-core desktop PC can be sufficient. If you simply need a lot of isolated zones, I think it's a better idea for them to be physically separate machines if security is important.
This is almost a hosting operation, but within a couple or few people. In general, I like powerful hardware, and I have genuine application for it. I run a lot of my own services because, and this is one of the considerable reasons behind me purchasing a large server, /I want to/
I didn't fall off the turnip truck yesterday and start having wet dreams about some mystical contraption known as a server. I've dealt with servers for years, and I enjoy doing it. It's my hobby, and expanding upon that for me is educational and entertaining.
As for internet, I have a symmetrical gigabit connection, not that this is too important since all the server users will have near constant physical access to the machine, but being the point of a server is to, well, serve, I have a reasonable connection to do that on.
Ask yourself two questions:
1) What workload do you have...
2) Does the load scale across multiple cores?
You may be better off overall with two 12 core machines than one 24 core one - for both redundancy and performance. Likely to be simpler/cheaper too. And easy to scale to as many cores as you could ever dream of!
1. A large variety of applications varying from web, email, and file, to virtual workstation, game server, and experiment hosting.
2. Yes.
As for the core count, I've had my eye on a 4 CPU 6 core Xeon machine that's going for around 600 bucks on ebay, comes with 128GB of RAM in two nodes. I'm not a fan of having two nodes, which is why I'm still looking, but the example serves to illustrate a point I am trying to make. I am trying to spend money in increments, such that one machine can be expanded into faster and faster solutions.
You have to understand these old servers are sold exactly because they've become too cumbersome to run. And because their support contracts ran out I suppose, but the point is that people felt they were better off buying new ones. Ivy Bridge is at this point old hat of nearly a decade old.
I understand that, but for my purposes (and more importantly, budget), they still provide me with the performance I require at a power consumption I'm not upset by. It's also why I do want to edge closer towards newer equipment. My current X5650 is actually quite good, and is yet older than Ivy Bridge, so I have some absolute bottom line of performance expectations with it.
Now, as for a few other questions people are asking:
1. Why don't you use desktop hardware
A: Because it doesn't scale well, the power consumption will be higher for the same performance range, and I genuinely believe I need, and do want a high core count server, designed to be a server.
2. Why don't you just use multiple machines?
A: Because I already am. This is intended to be one server out of 3, with the other two being X5650 storage servers holding SATA SSDs and/or hard drives.
The one and only good suggestion I've seen is to look for E7 in particular. This crossed my mind, but I had the thought that E7 might end up being significantly more expensive than E5s. I'll keep looking around with that in mind.
tl;dr I know what I'm doing, I'm not stupid, I've taken all of your concerns into account before you've placed them, and I am perfectly willing and able to maintain a Xen environment. While I understand the wish to ensure that people don't do stupid things with money, I'd kindly request that people let me worry about that one. Not trying to be rude or dismissive, though it may seem.