We just moved from 3.1 to 3.4 and in restoring our Windows 7 guest virtual machines from backup they are not starting. Please see the error below.
kvm: -drive file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on: file system may not support O_DIRECT
kvm: -drive file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on: could not open disk image /var/lib/vz/images/201/vm-201-disk-1.qcow2: Could not open '/var/lib/vz/images/201/vm-201-disk-1.qcow2': Invalid argument
TASK ERROR: start failed: command '/usr/bin/kvm -id 201 -chardev 'socket,id=qmp,path=/var/run/qemu-server/201.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -vnc unix:/var/run/qemu-server/201.vnc,x509,password -pidfile /var/run/qemu-server/201.pid -daemonize -name CRVMPTS1 -smp '1,sockets=1,cores=1,maxcpus=1' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000' -vga qxl -no-hpet -cpu 'kvm64,hv_spinlocks=0xffff,hv_relaxed,+lahf_lm,+x2apic,+sep' -m 2048 -k en-us -device 'qxl,id=vga1,ram_size=67108864,vram_size=33554432,bus=pci.0,addr=0x18' -device 'intel-hda,id=sound5,bus=pci.0,addr=0x19' -device 'hda-micro,id=sound5-codec0,bus=sound5.0,cad=0' -device 'hda-duplex,id=sound5-codec1,bus=sound5.0,cad=1' -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' -spice 'tls-port=61000,addr=127.0.0.1,tls-ciphers=DES-CBC3-SHA,seamless-migration=on' -device 'virtio-serial,id=spice,bus=pci.0,addr=0x9' -chardev 'spicevmc,id=vdagent,name=vdagent' -device 'virtserialport,chardev=vdagent,name=com.redhat.spice.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:d6cd784be291' -drive 'if=none,id=drive-ide2,media=cdrom,aio=native' -device 'ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200' -drive 'file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on' -device 'virtio-blk-pci,drive=drive-virtio0,id=virtio0,bus=pci.0,addr=0xa,bootindex=100' -netdev 'type=tap,id=net0,ifname=tap201i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=B2:5C:7E:1A0:AB,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' -rtc 'driftfix=slew,base=localtime' -global 'kvm-pit.lost_tick_policy=discard'' failed: exit code 1
kvm: -drive file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on: file system may not support O_DIRECT
kvm: -drive file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on: could not open disk image /var/lib/vz/images/201/vm-201-disk-1.qcow2: Could not open '/var/lib/vz/images/201/vm-201-disk-1.qcow2': Invalid argument
TASK ERROR: start failed: command '/usr/bin/kvm -id 201 -chardev 'socket,id=qmp,path=/var/run/qemu-server/201.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -vnc unix:/var/run/qemu-server/201.vnc,x509,password -pidfile /var/run/qemu-server/201.pid -daemonize -name CRVMPTS1 -smp '1,sockets=1,cores=1,maxcpus=1' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000' -vga qxl -no-hpet -cpu 'kvm64,hv_spinlocks=0xffff,hv_relaxed,+lahf_lm,+x2apic,+sep' -m 2048 -k en-us -device 'qxl,id=vga1,ram_size=67108864,vram_size=33554432,bus=pci.0,addr=0x18' -device 'intel-hda,id=sound5,bus=pci.0,addr=0x19' -device 'hda-micro,id=sound5-codec0,bus=sound5.0,cad=0' -device 'hda-duplex,id=sound5-codec1,bus=sound5.0,cad=1' -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' -spice 'tls-port=61000,addr=127.0.0.1,tls-ciphers=DES-CBC3-SHA,seamless-migration=on' -device 'virtio-serial,id=spice,bus=pci.0,addr=0x9' -chardev 'spicevmc,id=vdagent,name=vdagent' -device 'virtserialport,chardev=vdagent,name=com.redhat.spice.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:d6cd784be291' -drive 'if=none,id=drive-ide2,media=cdrom,aio=native' -device 'ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200' -drive 'file=/var/lib/vz/images/201/vm-201-disk-1.qcow2,if=none,id=drive-virtio0,format=qcow2,aio=native,cache=none,detect-zeroes=on' -device 'virtio-blk-pci,drive=drive-virtio0,id=virtio0,bus=pci.0,addr=0xa,bootindex=100' -netdev 'type=tap,id=net0,ifname=tap201i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=B2:5C:7E:1A0:AB,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' -rtc 'driftfix=slew,base=localtime' -global 'kvm-pit.lost_tick_policy=discard'' failed: exit code 1