Example log excerpt (libvirt log) for trying to attach a volume with snapshot to a running guest VM (manual test): 2016-07-27 10:31:23.135+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2313 : Found free PCI slot 0000:00:05 2016-07-27 10:31:23.135+0000: 16633: debug : qemuDomainPCIAddressReserveAddr:2114 : Reserving PCI slot 0000:00:05.0 (multifunction='off') 2016-07-27 10:31:23.193+0000: 16633: debug : qemuSetupDiskPathAllow:60 : Process path /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d480 5690e81b for disk 2016-07-27 10:31:23.194+0000: 16633: debug : qemuSetupDiskPathAllow:60 : Process path /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.2f3c2d0e-5315-48f3-9fc7-7e39 2c7958e1 for disk 2016-07-27 10:31:23.194+0000: 16633: debug : qemuSetupDiskPathAllow:60 : Process path /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0 for disk 2016-07-27 10:31:23.197+0000: 16633: debug : virCommandRunAsync:2282 : About to run /usr/lib/libvirt/virt-aa-helper -p 0 -r -u libvirt-4df0bca7-5e5c-47b8-9c27-d40277351fb0 -f /mnt/quobyte-volume/abfa1002557ab2b2 1ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b 2016-07-27 10:31:23.197+0000: 16633: debug : virCommandRunAsync:2285 : Command result 0, with PID 10895 2016-07-27 10:31:23.521+0000: 16633: debug : virCommandRun:2142 : Result status 0, stdout: '' stderr: '' 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2270 : PCI slot 0000:00:01 already in use 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2270 : PCI slot 0000:00:02 already in use 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2270 : PCI slot 0000:00:03 already in use 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2270 : PCI slot 0000:00:04 already in use 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressGetNextSlot:2313 : Found free PCI slot 0000:00:05 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainPCIAddressReserveAddr:2114 : Reserving PCI slot 0000:00:05.0 (multifunction='off') 2016-07-27 10:31:23.521+0000: 16633: debug : qemuDomainObjEnterMonitorInternal:1278 : Entering monitor (mon=0x7fc904181380 vm=0x7fc8f80117a0 name=instance-00000015) 2016-07-27 10:31:23.521+0000: 16633: debug : qemuMonitorAddDrive:3011 : mon=0x7fc904181380 drive=file=/mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f30 0-4927-9231-d4805690e81b,if=none,id=drive-virtio-disk1,format=qcow2,serial=605eb107-baf5-4a10-a2b9-60a3a77f2fc0,cache=none,aio=native 2016-07-27 10:31:23.521+0000: 16633: debug : qemuMonitorJSONAddDrive:3126 : drive_add command not found, trying HMP 2016-07-27 10:31:23.521+0000: 16633: debug : qemuMonitorJSONCommandWithFd:264 : Send command '{"execute":"human-monitor-command","arguments":{"command-line":"drive_add dummy file=/mnt/quobyte-volume/abfa1002557a b2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b,if=none,id=drive-virtio-disk1,format=qcow2,serial=605eb107-baf5-4a10-a2b9-60a3a77f2fc0,cache=none,aio=native" },"id":"libvirt-16"}' for write with FD -1 2016-07-27 10:31:23.521+0000: 16633: debug : qemuMonitorSend:959 : QEMU_MONITOR_SEND_MSG: mon=0x7fc904181380 msg={"execute":"human-monitor-command","arguments":{"command-line":"drive_add dummy file=/mnt/quobyte- volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b,if=none,id=drive-virtio-disk1,format=qcow2,serial=605eb107-baf5-4a10-a2b9-60a3a77f2fc0,cache=none,aio=native"},"id":"libvirt-16"} fd=-1 2016-07-27 10:31:23.521+0000: 16628: debug : qemuMonitorIOWrite:504 : QEMU_MONITOR_IO_WRITE: mon=0x7fc904181380 buf={"execute":"human-monitor-command","arguments":{"command-line":"drive_add dummy file=/mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b,if=none,id=drive-virtio-disk1,format=qcow2,serial=605eb107-baf5-4a10-a2b9-60a3a77f2fc0,cache=none,aio=native"},"id":"libvirt-16"} len=350 ret=350 errno=11 2016-07-27 10:31:23.632+0000: 16628: debug : qemuMonitorIOProcess:396 : QEMU_MONITOR_IO_PROCESS: mon=0x7fc904181380 buf={"return": "could not open disk image /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b: Could not open backing file: Could not open '/mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.2f3c2d0e-5315-48f3-9fc7-7e392c7958e1': Permission denied\r\n", "id": "libvirt-16"} len=399 2016-07-27 10:31:23.632+0000: 16628: debug : qemuMonitorJSONIOProcessLine:157 : Line [{"return": "could not open disk image /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b: Could not open backing file: Could not open '/mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.2f3c2d0e-5315-48f3-9fc7-7e392c7958e1': Permission denied\r\n", "id": "libvirt-16"}] 2016-07-27 10:31:23.632+0000: 16628: debug : qemuMonitorJSONIOProcessLine:177 : QEMU_MONITOR_RECV_REPLY: mon=0x7fc904181380 reply={"return": "could not open disk image /mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.1a65bc67-f300-4927-9231-d4805690e81b: Could not open backing file: Could not open '/mnt/quobyte-volume/abfa1002557ab2b21ec218a86487dd92/volume-605eb107-baf5-4a10-a2b9-60a3a77f2fc0.2f3c2d0e-5315-48f3-9fc7-7e392c7958e1': Permission denied\r\n", "id": "libvirt-16"} 2016-07-27 10:31:23.632+0000: 16628: debug : qemuMonitorJSONIOProcess:226 : Total used 399 bytes out of 399 available in buffer 2016-07-27 10:31:23.632+0000: 16633: debug : qemuMonitorJSONCommandWithFd:269 : Receive command reply ret=0 rxObject=0x7fc91cc96ea0 2016-07-27 10:31:23.632+0000: 16633: error : qemuMonitorTextAddDrive:2611 : operation failed: open disk image file failed