[libvirt-users] snapshot-create error

[Hong-Hua.Yin at freescale.com]

Hi,

What's the difference between QEMU snapshot and libvirt snapshot? 

# qemu-img create -f qcow2 disk.img 512
Formatting 'disk.img', fmt=qcow2 size=512 encryption=off cluster_size=65536 lazy_refcounts=off

# qemu-img info disk.img
image: disk.img
file format: qcow2
virtual size: 512 (512 bytes)
disk size: 136K
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

# /usr/bin/qemu-system-ppc -M ppce500 -enable-kvm -m 512 -nographic -kernel /dev/shm/uImage -initrd /dev/shm/ramdisk -append "root=/dev/ram rw console=ttyS0,115200" -serial tcp::4444,server,telnet -snapshot -hda disk.img
QEMU 1.7.0 monitor - type 'help' for more information
(qemu) QEMU waiting for connection on: telnet:0.0.0.0:4444,server

(qemu) savevm
(qemu) info snapshot
unknown command: 'info snapshot'
(qemu) info snapshots
ID        TAG                 VM SIZE                DATE       VM CLOCK
1         vm-20140709035738      173M 2014-07-09 03:57:38   00:00:07.401


Is there any special qemu command options or kernel configurations to allow libvirt create snapshot?

I got the error as below:

virsh # snapshot-create snap
error: unsupported configuration: internal snapshots and checkpoints require all disks to be selected for snapshot

The domain XML file is converted as below steps.
# cat >snap.args <<EOF
/usr/bin/qemu-system-ppc -name snap -M ppce500 -enable-kvm -m 512 -nographic -kernel /dev/shm/uImage -initrd /dev/shm/ramdisk -append "root=/dev/ram rw console=ttyS0,115200" -serial pty

# virsh domxml-from-native qemu-argv snap.args >snap.xml

# cat sdk.xml
<domain type='kvm'>
    <name>sdk</name>
    <memory unit='KiB'>524288</memory>
    <currentMemory unit='KiB'>524288</currentMemory>
    <vcpu placement='static'>1</vcpu>
    <os>
      <type arch='ppc' machine='ppce500'>hvm</type>
      <kernel>/dev/shm/uImage</kernel>
      <initrd>/dev/shm/ramdisk</initrd>
      <cmdline>root=/dev/ram rw console=ttyS0,115200</cmdline>
      <boot dev='hd'/>
    </os>
    <clock offset='utc'/>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>destroy</on_crash>
    <devices>
      <emulator>/usr/bin/qemu-system-ppc</emulator>
      <controller type='usb' index='0'/>
      <controller type='pci' index='0' model='pci-root'/>
      <serial type='pty'>
        <target port='0'/>
      </serial>
      <console type='pty'>
        <target type='serial' port='0'/>
      </console>
      <memballoon model='virtio'>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
      </memballoon>
    </devices>
</domain>


Best Regards,
Olivia