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Description of problem: Creating internal snapshot fails with data-plane. Version-Release number of selected component (if applicable): Host: Kernel:3.10.0-325.el7.x86_64 qemu-kvm-rhev:qemu-kvm-rhev-2.3.0-31.el7.x86_64 Guest: Kernel:3.10.0-325.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1. Boot guest with data-plane # /usr/libexec/qemu-kvm -name rhel7.2 -machine pc-i440fx-rhel7.2.0,accel=kvm \ -cpu SandyBridge -m 4G,slots=256,maxmem=40G -numa node \ -smp 4,sockets=2,cores=2,threads=1 \ -uuid 82b1a01e-5f6c-4f5f-8d27-3855a74e6b61 \ -netdev tap,id=hostnet0 \ -device virtio-net-pci,netdev=hostnet0,id=net0,mac=12:54:00:5c:88:61 \ -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vgamem_mb=16 \ -vnc 0.0.0.0:1 \ -monitor stdio \ -qmp tcp:0:5555,server,nowait \ -serial unix:/tmp/monitor,server,nowait \ -object iothread,id=iothread0 \ -drive file=/home/rhel7.2.virtio.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \ -device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0,iothread=iothread0 \ 2. Create internal snapshot. This job can not be finished(wait 30 miniutes). (qemu) savevm 3. check the image info, no snapshot exists. # qemu-img info /home/rhel7.2.virtio.qcow2 image: /home/rhel7.2.virtio.qcow2 file format: qcow2 virtual size: 20G (21474836480 bytes) disk size: 13G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false Actual results: '(qemu) savevm' can not be finished even after 30 minutes. Expected results: '(qemu) savevm' should finish quickly and correctly. Additional info: 1. Without data-plane, '(qemu) savevm' will be finished with 5 seconds.
Fixed in RHEL 7.3 qemu-kvm-rhev due to upstream QEMU 2.6 rebased. Denis Lunev fixed migration/savevm.c. I tested qemu-kvm-rhev-2.6.0-4.el7.
Reproduce: qemu-kvm-rhev-2.3.0-31.el7 kernel-3.10.0-505.el7.x86_64 Boot guest with virtio-blk data-plane, do savevm in qmp. Both guest and qmp become unresponsive. And no snapshot is generated. Steps: 1. # /usr/libexec/qemu-kvm -m 1024,slots=10,maxmem=32G -smp 8 -cpu host \ -object iothread,id=iothread0 -drive id=drive_image1,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/guest/rhel73.qcow2 -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=0,bus=pci.0,addr=04,iothread=iothread0 \ -device e1000,mac=9a:65:66:67:68:69,id=id9yQ73x,netdev=idT9phLU,bus=pci.0,addr=05 -netdev tap,id=idT9phLU -usb -device usb-tablet,id=usb-tablet1 -vga cirrus -vnc :0 -monitor stdio 2. (qemu) savevm // no response 3. # qemu-img info rhel73.qcow2 image: rhel73.qcow2 file format: qcow2 virtual size: 40G (42949672960 bytes) disk size: 8.3G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false Verify: qemu-kvm-rhev-2.6.0-24.el7 kernel-3.10.0-505.el7.x86_64 With same steps as above, a snapshot has been generated successfully and guest works well. # qemu-img info rhel73.qcow2 image: rhel73.qcow2 file format: qcow2 virtual size: 40G (42949672960 bytes) disk size: 9.1G cluster_size: 65536 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 vm-20160913030723 838M 2016-09-13 03:07:23 00:01:51.988 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false So the bug is fixed.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2673.html