[libvirt] save / restore for KVM

[Matthias Pfafferodt]

Hello,

I try to save a KVM domain which has its hard disk on a LVM volume. I can 
execute the command to save the domain but restore fails

# virsh list
 Id Name                 State
----------------------------------
  3 kvm-linux03          running
  4 kvm-linux01          running

# virsh save kvm-linux01 ./kvm-linux01.ram
Domain kvm-linux01 saved to ./kvm-linux01.ram

# virsh list
 Id Name                 State
----------------------------------
  3 kvm-linux03          running

# virsh restore ./kvm-linux01.ram
libvir: QEMU error : operation failed: failed to start VM
error: Failed to restore domain from ./kvm-linux01.ram



I tried to save and restore this domain using kvm directly

# /usr/bin/qemu-kvm -m 1024 -boot c -drive 
file=/dev/virtual/kvm_linux01,if=ide,index=0,boot=on -net 
nic,macaddr=00:16:3e:00:01:02,vlan=0 -net 
tap,fd=24,script=,vlan=0,ifname=vnet3 
(qemu) savevm kvm-linux01.ram
Device id0-hd0 does not support VM state snapshots
(qemu)

Here I get an error message which I also found on the qemu homepage: to save a 
qemu vm the hard disk must be a file using the qcow format. But in the libvirt 
documentation there is no hint to this limitation. Is it possible to save the 
state of a kvm vm using physical hard disks with libvirt?

Kind regards

Matthias Pfafferodt
-- 
Matthias Pfafferodt - http://www.mapfa.de
Matthias.Pfafferodt <at> mapfa.de