Linux · Virtualization: QEMU/KVM & libvirt

A VM's image file on the host is far bigger than the data df reports inside the guest. Why, and how do you reclaim the space?

Answer locked. Get the free KnowCard app to reveal it — plus spaced-repetition review so it actually sticks.

This is one card from the KnowCard library — thousands more across SAP, Linux, Python and more. In the app you get the answer, AI explanations, and cards that come back right before you would forget them. Free to start on iOS, Android or the web.

More in Virtualization: QEMU/KVM & libvirt

When you shut down a KVM host, what happens to the running VMs — and where does their state go?

What is the relationship between QEMU and KVM, and why do RHEL and SUSE lean on the pair for enterprise virtualization?

You want to run KVM guests on a cheap cloud VM you rented from a hosting provider. Why does that usually not work?

Beyond ordinary x86 emulation, what makes QEMU able to run software built for a completely different CPU architecture?

KVM is often called a hypervisor, but what does the KVM kernel module actually do — and not do — on its own?

How do you check from the shell whether a CPU supports the hardware virtualization KVM requires, and what does an empty result mean?

Start learning today

Free to start — download the app or use it in your browser.