Hello,
I was wondering which server would be suitable for running multiple csgo servers and one or two rusty servers. My estimate for csgo is around 1 core and 2-3 GB of RAM, but I am unsure about the resource usage of a vanilla Rust server.

In terms of server performance, I'm not sure whether to go for single-core (MC-32) or more (SP-128) MC-32. I don't have any experience with servers outside of the original game, so I'm not sure which one to choose.

Finally, I'm also unsure about whether to continue using xenserver virtualization. Do you have any recommendations for me?

According to my research, MC-32 should be sufficient to run multiple csgo and Rust servers simultaneously. However, Rust's resource usage can reach up to 5-10 GB of RAM, which is based on data from a popular Rust server with an average of 100 online players.

Regarding virtualization, it is important to note that it can lead to reduced performance. I recall writing detailed statistics on the impact of kernel virtualization on these forums a year or two ago. Although I had to search a bit to find it in the regular Centos kernel, the efficiency was noticeably reduced. It's important to weigh the pros and cons before deciding whether to use virtualization or not.

First off, let's talk about the hardware for your CS:GO and Rust servers. You've got a decent estimate for CS:GO —1 core and 2-3 GB of RAM per server sounds about right. However, Rust is a bit more demanding, especially when it comes to CPU and RAM usage. A vanilla Rust server can easily eat up 6-8 GB of RAM and will be more CPU intensive, particularly if you have a lot of players or mods running on it.

Given that you're looking at potentially running multiple CS:GO servers and a couple of Rust servers, I'd lean towards a server with more cores and RAM. The MC-32 might be sufficient if you're running, say, 4-5 CS:GO servers with one Rust server, but it could get tight. The SP-128, on the other hand, offers more breathing room. It has more cores and can handle a larger workload, especially if you're expecting higher player counts or want to run mods on the Rust servers.

Regarding virtualization, XenServer is solid, but it's getting a bit dated and doesn't have the same level of community support or features as some other options. You might want to consider moving to something like Proxmox or even VMware ESXi. Both offer more modern features, better performance, and are easier to manage. Proxmox, in particular, has a great community and offers a lot of flexibility in terms of managing containers and VMs.

Also, don't forget to consider your network setup. Running multiple game servers will require a good amount of bandwidth, and you'll want to make sure you have DDoS protection in place, especially for Rust servers, as they can be a target.
If you're going to run a decent number of servers and want to future-proof your setup, the SP-128 would be a better choice. It's more expensive, but it gives you the headroom you'll need for Rust and multiple CS:GO servers. And yeah, maybe consider moving away from XenServer to something more up-to-date like Proxmox, which will give you better performance and easier management.