Arch Linux

ataraxia

Member

From: Pittsburgh

Registered: 2007-05-06

Posts: 1,553

KVM guests hang, but only on Arch

Hey there folks, long time no see. I haven't been using Arch much lately, and this long-standing problem is a big reason why.

I like to use libvirt / qemu / KVM to run VMs. This works great when the host is Debian, Ubuntu, or Fedora. But on Arch, the guest will reliably hang up completely before I can even get through the installation. The guest will just stop moving, and CPU usage drops to 0.

It appears to always happen during an I/O-heavy activity inside the guest - usually while packages are being installed. This makes me suspect something is off in the storage subsystem of Arch's kernel (on the host).

I use XFS on root and VFAT on /boot (booting EFI).  I have not tested other filesystems than XFS, but I do wonder about that. Hardware is an NVME SSD, Intel 600p, attached to an ASUS ROG STRIX z270e board.

Nothing is unusual in my setup at all - I keep things simple in more ways than one and don't tweak.

This has been happening reliably since at least late 2017.

The problem only occurs with qemu / KVM. If I use Virtualbox instead, all is well.

Anyone got any clue about this? Or can reproduce it? Note that I'm not running Arch right now, so I won't be able to test any suggestions promptly - I apologize for being hard to support here.

x33a

Forum Fellow

Registered: 2009-08-15

Posts: 4,587

Re: KVM guests hang, but only on Arch

I will start debugging by trying a different filesystem. Also, does nothing get logged in either the guest or the host when the issue happens?