Re: [Qemu-devel] [Bug 1434779] [NEW] qemu hangs on live-migration with storage(virtual machine: windows Server 2008 with only one disk )

[Halsey Pian]

> -----Original Message-----
> From: address@hidden [mailto:address@hidden
> On Behalf Of Stefan Hajnoczi
> Sent: 2015年3月23日 21:32
> To: Bug 1434779
> Cc: address@hidden
> Subject: Re: [Qemu-devel] [Bug 1434779] [NEW] qemu hangs on live-migration 
> with storage(virtual machine: windows Server 2008
> with only one disk )
> 
> On Sat, Mar 21, 2015 at 07:44:37AM -0000, youyunyehe wrote:
> > We are using “Windows Server 2008” with qemu-kvm-2.0.1 (linux 
> > kernel:3.10.0) as a host of  a VM.
> 
> Please give the exact qemu-kvm package version and Linux distro name.
> The code in qemu.git/master is slightly different so maybe the issue no 
> longer happens, but it would be worth looking at the exact
> source code your qemu-kvm is built from.

[Halsey] I also recreated this issue today, qemu hangs at bdrv_rw-co() -> 
bdrv_prwv_co() -> aio_poll(0 -> qemu_poll_ns() -> ppoll().  I'm just call 
bdrv_write to write data to qcow2 file. My qemu version is qemu-2.2.0.

> I have CCed Jeff Cody, who maintains drive-mirror.
> 
> > Using drive_mirror to do  live-migration on the same host for
> > different disks Local disk: /sf/data/local/
> > Shared disk(iscsi): /sf/other/local/    ---  the disk is busy, the IO rate 
> > is  about  30MB/s
> > qemu-system-x86_64 -k en-us -m 2048 -smp 2 -vnc :3100 -usbdevice
> > tablet -boot c -enable-kvm -drive
> > file=/sf/data/local/vm-disk-1.qcow2,if=none,id=drive-ide0,cache=none,a
> > io=native -device
> > ide-hd,bus=ide.0,unit=0,drive=drive-ide0,id=ide0,bootindex=100
> >
> > Step 1:
> > Start migration: Drive_mirror -f drive-ide0
> > /sf/other/local/test.qcow2
> >
> > Step 2:
> > When detect the migration has completed, then send cmd:
> > block_job_complete -f drive-ide0
> >
> > Step 3:
> > send cmd: info status
> > What surprised me is that the qemu monitor reports can’t be connected.
> >
> > Then find bellows:
> > The  qemu process hangs on the
> > mirror_run->bdrv_drain_all->aio_poll->qemu_poll_ns->ppoll (), None
> > events were received and poll forever. I don’t know why the aio can’t be 
> > responsed. This case is hardly to be generated but it really
> happens sometimes . I’m looking forward to getting help from you .
> > The stack capture snapshot: