I recently found out about a Linux Distro named Q4OS and I wanted to test out their claim that it only requires 256 MB of ram when using the trinity desktop environment. However, when I used the live cd in virt-manager with 256 MB or ram, it just kernel panicked at boot. So I then tried it with 512 MB of ram. In addition to some issues that are not present when you are using at least 1 GB of ram, such as “sudo apt update” causing the entire VM to become unresponsive, I noticed that it seemed to actually use anywhere between 290 MB to 370 MB of ram when the only thing running was the process viewer (which is htop).
Obviously, this is still very low for a modern Linux distro but I was wondering how accurate VMs are for testing ram usage.
And, yes I know that it would be pretty much useless on a PC that only had 256 MB of ram even if it did work. I’m actually checking the ram usage because there is a possibility that I may be using a very old computer of mine that only has 1 GB of ram at some point in the future. So I’m just testing it and eventually other distros out to to see which one I’m going to end up using (assuming I do actually end up even using that computer).
Docker, e.g. containers, are actually a process isolation system similar but not exactly the same as a chroot if you are familiar with that. It’s an isolation of resources, but not so hardware isolated like a full fat VM. For example, adding a GPU to a VM requires handing over the full PCIe hardware interface, with one interface per VM. Where as containers can just bind mount the device files in /dev and multiple containers can share the same GPU hardware. Containers aren’t virtualizating anything, just isolating processes from each other in a standardized way.