Hi, I was facing a weird behavior when I used the one disk image file on 2 virtual machines at the same time.
I made the instance of a virtual machine, using the below command. $ qemu-system-x86_64 -smp 2 -m 1024 -hda 10G.qcow2 -enable-kvm When the OS(Ubuntu 14.04 64bit) was booted up, I made an another one, using same command. $ qemu-system-x86_64 -smp 2 -m 1024 -hda 10G.qcow2 -enable-kvm Then, I had 2 virtual machines, using same disk image file. When I made a directory on first virtual machine, using the command like below. $ mkdir test1 The "test1" directory wasn't showed another virtual machine. And, I made a directory on second virtual machine, using the command like below. $ mkdir test2 The "test2" directory wasn't showed another virtual machine, too. Then, I shut the all virtual machines down. I tried to mount the disk image file on my host machine. $ sudo modprobe nbd $ sudo qemu-nbd -c /dev/nbd0 $ sudo mount /dev/nbd0p1 /mnt/10G Then, I checked what the file is showed. The result was that "test2" directory only lived. Where is the "test1" directory? This is the weird behavior on my test. Before my test, I created a disk image file and installed the OS on the disk image, using the commands like below. $ qemu-img create -f qcow2 -o preallocation=metadata 10G.qcow2 10G $ qemu-system-x86_64 -smp 2 -m 2048 -hda 10G.qcow2 -cdrom ../iso/ubuntu-1404.2-desktop-x86_64.iso -enable-kvm
