where does the extra space in virtual storage come from?

[Osaidaz]

Hi

something I don't understand about virtual storage...

for example:

when I create a VM and I assign 1TB hard Drive to it , where does this 1TB come from? lets say my physical machine has only 512GB, I'm still able to assign 1TB to VM! how? where does the extra 500GB come from? same things with the RAM, I can assign more RAM to my VM than I have in my physical machine

sorry if the answer is obvious ,I'm new to this and its very confusing

[a_p_]

There's no extra space, and if the physical disk space is exhausted, then the VM won't be able to store data anymore.

A thin, or sparse virtual disk is basically a file (or an object) which is created with a small size, and grows as data is written from within the guest OS. The guest is only aware of the presented/provisioned size, but not of the physical available disk space. Presenting a virtual disk with more logical capacity than physically available is risky, and you need to monitor the physical disk usage to avoid issues.

André