Does anyone have tips on troubleshooting live migration? I'm not sure if this should be a qemu question or a kvm one. I've got several E5-2650 servers running in test environment, kernel 3.10.26 and qemu 1.7.0. If I start a VM guest (say ubuntu, debian, or centos), I can migrate it around from host to host to host just fine, but if I wait awhile (say 1 hour), I try to migrate and it succeeds but the guest is hosed. No longer pings, cpu is thrashing. I've tried to strace it and don't see anything that other working hosts aren't doing, and I've tried gdb but I'm not entirely sure what I'm doing. I tried downgrading to qemu 1.6.1. I've found dozens of reports of such behavior, but they're all due to other things (migrating between different host CPUs, someone thinking it's virtio or memballoon only to later find a fix like changing machine type, etc). I'm at a loss. I've tried replacing the virtio disk/network with sata/e1000, no difference. I'm just trying to figure out where to go from here. I've got a core dump of the qemu process that was spinning, and I can reproduce it fairly easily. Here's an example qemu cmdline: /usr/bin/qemu-system-x86_64 -machine accel=kvm -name VM12 -S -machine pc-i440fx-1.7,accel=kvm,usb=off -m 512 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid dd10a210-ab41-4cc6-a8f2-51113dd39515 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/VM12.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -drive file=/dev/sdd,if=none,id=drive-virtio-disk0,format=raw,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=2 -drive if=none,id=drive-ide0-1-0,readonly=on,format=raw,cache=none -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=1 -netdev tap,fd=29,id=hostnet0,vhost=on,vhostfd=31 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=02:00:39:28:00:01,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/VM12.agent,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=VM12.vport -device usb-tablet,id=input0 -vnc 0.0.0.0:1 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
