For mdadm, it stores the metadata on the drives themselves. As long as your os is separate, yes, it should be just fine and detect automatically. After install it should just be a mdadm --assemble --scan and off to the races.

That said, I will always recommend backups. You never know what will happen.

In terms of docker, yes you can back things up and move them over. That said I recommend having your docker contents that need to be persistent as part of a mount somewhere, so that instead of needing to copy them around, you just have a compose that points to a mount.

Makes backups easier too.

Proxmox is based on Debian the way Ubuntu is, but more highly focused and without departing from main Debian strategies.

Proxmox is a kernel and set of tools for managing virtual machines and containers, in this case LXCs. These are different from docker, they share the kernel with the host but have isolation at namespaces (user id's, process trees, network views, etc). They boot in seconds because they bypass hardware virtualization like you'd have with a VM.

I'd say gaming is better off as its own project effort. You could do things like GPU pass through and a dedicated VM for gaming, but you would be adding a pretty hefty layer of complication. If you dont need to convert av1 to something else, I'd just go with a 7th+ gen iGPU, and dont worry about it. Mine are 7th-10th gen, I have dozens of TBs of media, and they just chug along without issue handling somewhere between 4 and 6 streams at typical top use, mostly streamed without transcoding anyway. AV1 for the source file, you'll be transcoding almost everything because most devices dont support native decode anyway, so I don't personally find it worth it yet.

Just to mention, your Mac (if its an M series) can handle LLMs reasonably. I have an M2 Mac mini that runs some models, but my web interface for accessing those models is hosted on an LXC on one of my proxmox nodes.

It mostly gets used for local audio transcription and summaries, though occasional I'll let it do other things like autocompletes for code (but not generating code, I don't consider generated code to be useful).

Debian is the OS.

Proxmox builds on Debian to turn it into a hypervisor. That's an OS for managing VMs and containers. Proxmox (like most hypervisors) gives you a handy webinterface.

There are easier hypervisors to use, but Proxmox is great for learning, and allows you to expand well later.

tbh, except for gaming and AI, you don't need nearly as much processing power as you might think. I run most of my stuff on a (fairly new, can't remember which one exactly) i5, and it sits at an average 2-3% CPU usage, with the maximum its recorded being 10.9% (there's two VMs and 8 containers running on it). 11th gen i5 will probably be more than enough to start with.

In my non-professional opinion, what you really want to look at is how much power your system is going to use when idle, since that's what (small) servers are doing most of the time. This is not something specified by manufacturers, and it depends on all the parts going into the computer (CPU, mainboard, PSU, fans, how the BIOS is set up, ...).

I would also recommend getting at least 16 GB of RAM (honestly I would say 32, if not for the current prices). Containers don't use too much, but if you want to set up VMs for services, each VM will want at least 2-4 GB for itself.

LXC-Containers (https://en.wikipedia.org/wiki/LXC) are like extremely lightweight and slightly less secure Linux VMs. They are similar to Docker, but while Docker is containerizing applications, LXC containerizes Linux distros.

I'd still say no.

You don't really want a desktop task to crash and take down all of your services in one shot. As a VM with GPU pass through maybe, but not really in that beginner territory.