QEMU/KVM first impressions

[oshunluvr]

I started converting to QEMU/KVM from VirtualBox this weekend. I don't have much time with it yet, but thought it was worth starting the conversation.
in QEMU.

VM Conversion: The cli tools to convert the drives worked well but for some reason none of the converted Windows disks will boot. There must be a reason because ALL the linux drives did no problem. I was able to create a new Windows 10 client no problem.

Sharing files and folders: There apparently is a way to directly share a folder but I failed at first attempt on a Windows 10 client. Then I just did a samba connection and that worked well. The failed attempt at the folder resulted in preventing the VM from booting. The log file revealed the fact this that I had deleted the folder without removing it from the VM was the cause and restoring the empty folder allowed me to boot, and then I removed the connection from the VM.

USB drive: I was able to connect a USB stick on the Linux host to the Windows Client without too much trouble.

Biggest gripes so far:

The VM window doesn't close when you "power down" the client. Hopefully just a setting I haven't discovered.
The nice little System Tray menu is partially hidden on my system because I have my panel on the left rather than top or bottom. This rises to a bug IMO:


There doesn't seem to be a way to scroll through them and the top and bottom VMs are cut off.


I'll have more to say later but so far I like the simple interface. Some things like file and clipboard sharing are more difficult. I want to configure the pass through for the video hardware to see how that works. It seems easy to break the VMs, but I could do that in Vbox too. I suspect some of my difficulties are due to the change in how things are done.

If you're going to try this, you'll want to uninstall the guest editions stuff from the VM either after or before the conversion. I didn't have trouble with either method.

[Schwarzer Kater]

Unfortunately I don't have any spare time to try it, so thank you for your impressions.

Have you had time to do any performance comparisons between VMs in QEMU/KVM and VirtualBox 6.1.x yet?

[claydoh]

qemu/kvm (via virt-manager as a gui) is mounds better in terms of performance ootb, at the expense of some fewer features and a somewhat less familiar and less friendly UI.
But installing an OS with virt-manager is very easy, maybe easier than Virtualbox. Definitely faster. Feels almost native on my boring run of the mill i5 PC.

[GreyGeek]

What Claydoh says. My kvm VMs were lightening fast. I'd run them full screen and access to the kvm controls was gained merely by pushing the mouse to the top of the screen, which offered a drop down that allowed me to go out of full screen or switch to the control window.

Since I run BTRFS I put a nodatacow on the image directory, /var/lib/libvirt/images, before I created any images. And, I made my qcpw2 virtual disks static (fixed size, usually 40GB). Both BTRFS and qcow2 do COW but I never noticed my BTRFS slowing down while using a kvm vm.

I've run several distros under kvm and some do very well. Deepin 2.0 is one. UbuntuDDE is another. They go to full screen when the full screen button is clicked and run beautifully. Some others, like KDE Neon, openSUSE, Kubuntu, refuse to leave 1278X720, even when my full screen setting 1600X900 was chosen in the Monitor menu.

I'll never go back to VirtualBox.