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Re: [Qemu-devel] [Bug 1779120] Re: disk missing in the guest contingentl
From: |
贞贵李 |
Subject: |
Re: [Qemu-devel] [Bug 1779120] Re: disk missing in the guest contingently when hotplug several virtio scsi disks consecutively |
Date: |
Thu, 28 Jun 2018 14:00:42 -0000 |
Hi, Stefan.
(host)# rpm -qa | grep qemu-kvm
qemu-kvm-2.8.1-25.142.x86_64
(guest)# uname -r
3.10.0-514.el7.x86_64
I also tried the newest version of qemu-kvm, but it also met this issue.
The steps to reproduce this issue are below:
1)attach four virtio-scsi controller with dataplane to vm.
<controller type='scsi' index='0' model='virtio-scsi'>
<driver iothread='1'/>
<alias name='scsi0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x07'
function='0x0'/>
</controller>
<controller type='scsi' index='1' model='virtio-scsi'>
<driver iothread='2'/>
<alias name='scsi1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0a'
function='0x0'/>
</controller>
<controller type='scsi' index='2' model='virtio-scsi'>
<driver iothread='3'/>
<alias name='scsi2'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0b'
function='0x0'/>
</controller>
<controller type='scsi' index='3' model='virtio-scsi'>
<driver iothread='4'/>
<alias name='scsi3'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x0c'
function='0x0'/>
</controller>
2)attach 35 virtio-scsi disks(sda - sdai) to vm consecutively. One
controller has 15 scsi disks.
A example of disk xml is below:
<disk type='block' device='lun' rawio='yes'>
<driver name='qemu' type='raw' cache='none' io='native'/>
<source dev='/dev/mapper/360022a11000c1e0a0787bb2500000139'/>
<backingStore/>
<target dev='sda' bus='scsi'/>
<shareable/>
<alias name='scsi0-0-0-0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
You can write a shell script like this:
for((i=1;i++;i<=35))
do
virsh attach-device centos7.3_64_server scsi_disk_$i.xml
--config --live
done
This issue is a probabilistic event. If it does not appear, repeat the
above steps several more times.
Thank you!
On 2018/6/28 21:01, Stefan Hajnoczi wrote:
> Please post the following information:
> (host)# rpm -qa | grep qemu-kvm
> (guest)# uname -r
>
> What are the exact steps to reproduce this issue (virsh command-lines
> and XML)?
>
--
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1779120
Title:
disk missing in the guest contingently when hotplug several virtio
scsi disks consecutively
Status in QEMU:
New
Bug description:
Hi, I found a bug that disk missing (not all disks missing ) in the
guest contingently when hotplug several virtio scsi disks
consecutively. After rebooting the guest,the missing disks appear
again.
The guest is centos7.3 running on a centos7.3 host and the scsi
controllers are configed with iothread. The scsi controller xml is
below:
<controller type='scsi' index='0' model='virtio-scsi'>
<driver iothread='26'/>
<alias name='scsi0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x07'
function='0x0'/>
</controller>
If the scsi controllers are configed without iothread, disks are all
can be seen in the guest when hotplug several virtio scsi disks
consecutively.
I think the biggest difference between them is that scsi controllers
with iothread call virtio_notify_irqfd to notify guest and scsi
controllers without iothread call virtio_notify instead. What make it
difference? Will interrupts are lost when call virtio_notify_irqfd
due to race condition for some unknow reasons? Maybe guys more
familiar with scsi dataplane can help. Thanks for your reply!
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