Choice between real HDD and virtual (VDI, VMDK, etc.) for NAS organization. What are the pros and cons?

Question

Hard disks

Hello. I searched on the Internet and on the toaster, I did not find it.

The situation is as follows:
I'm building a home server, I want to deploy everything I need within the framework of virtualization (proxmox). That is, to have a number of virtual machines with their own internal network (the router will also be like a virtual machine). Initially, I planned to use 2-3 pieces of iron, so that one was only as network storage, the second was a router, the third was a virtualization server. In general, something like that. The idea came to place all this in one, but powerful piece of iron, which would cover all tasks. From my point of view, this looks practical.

Only one thing is not clear, if I deploy the NAS as a virtual machine, and the storage role will be virtual disks, how reliable it will be in cases of a sudden loss of electricity. I practically did not come across virtual disks and I have no idea how they react to this. With real, everything is more or less clear. Of course I plan to use a UPS, but still this question haunts me. I have a suspicion that in such a situation, after a sudden loss of electricity, the virtual disk file may simply stop being read.

I ask for your help dear experts. Perhaps someone came across such an implementation option and can share practical experience? I will be very grateful.

PS I considered the option to install debian, prokmox on it and deploy nas directly on the host machine, but I still want everything to be on virtual machines.

Answer 1

The idea came to place all this in one, but powerful piece of iron

Bad thought. As a person who has kept a network of exactly this configuration for many years (just now without nas) - I will say that this is a bad idea. Rather, it's all good as long as you're sitting at home. When you are away from home and there is a power outage, after which the virtual router gets into the position of a company machine gun - you have to patiently explain to your wife / child / someone else what you need to press on the keyboard to make it work.
I had to do this many times and once I got tired of it, I put Mikrotik as a router. And now, even if something happens to a server, at least I can always get to its console through iKVM.
The router makes sense to take out in a piece of iron.
NAS makes sense to put in a piece of iron - it's for backups, right? Are we among those admins who already do them?
This is a standard scheme for building a network of a small office, tested many times.

Answer 2

Ladies and gentlemen. Thank you for the detailed answers, you gave me food for thought, now I will think about how best to proceed in my situation based on your suggestions. I see no reason to further develop the topic, to argue, because each of the suggested answers makes sense. The question is closed.
PS I'll still collect NAS as a separate piece of hardware, for the following reasons and requirements:
1. A separate NAS still gives more features and benefits (I won't list it, I think it's clear what it is);
2. The NAS will work 24/7 and be used as a central storage, including for virtual machine images. I'll insert a pci-card, throw 10Gb optics between the NAS and the virtualization server so that there are no drawdowns;
3. It is possible to maintain power supply in case of power loss to a separate NAS longer than to a multi-core stoker;
4. In this regard, the UPS will be 2 pcs. 15-20 minutes is enough for the virtualization server to calmly collapse, but it seems to me that NAS should work for longer, you never know, suddenly important copying or backup occurs;
5. Having a separate NAS is less time consuming. maintenance in the long term when updating packages / distributions / resolving package dependencies / and the same work with disks.
The shared storage will be storage and the control center/monitoring/services will be virtualized.