Re: [ovirt-users] virtio-scsi drive order?

[Michal Skrivanek]

> On 16 Mar 2017, at 11:12, Yaniv Kaul  wrote:
> 
> 
> 
> On Thu, Mar 16, 2017 at 11:56 AM, Martin Polednik  > wrote:
> On 16/03/17 08:23 +0100, gflwqs gflwqs wrote:
> Hi list!
> When we upgraded our ovirt environment to 4.1 we get the virtio-scsi
> interface as default for virtual disks.
> We have seen a difference in drive order from when we used the virtio
> interface.
> 
> Before when we added disks the order of the drives were set by which order
> the disks was created.
> So if i had 1 disk as os disk it became vda and added a 50 GB disk that
> disk became vdb and then added another 8GB disk that became vdc.
> 
> But now when i add two additional disks with the virtio-scsi interface like
> the above when i reboot the vm the 50GB disk become sdc and the 8GB disk
> become sdb even that i created the 50GB disk first?
> How is the order decided in the virtio-scsi interface?
> What can i do to ensure that the disks come in the order that i create them?
> 
> Regards
> Christian
> 
> Could you post the XML (virsh -r list, note the domain
> number and virsh -r dumpxml $domainnumber) before and after adding the
> disks? Need to see whether there are also any iothreads or anything
> else.
> 
> It doesn't matter - the order of disk discovery on the SCSI bus (by udev?) is 
> quite random.
> You must use /dev/disk/by-id/scsi-…

well, it may in case we are actually doing something wrong with controllers or 
iothreads due to recent changes in that area.

> 
> Y.
>  
> 
> Thanks,
> mpolednik
> 
> 
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Re: [ovirt-users] virtio-scsi drive order?

[Yaniv Kaul]

On Thu, Mar 16, 2017 at 11:56 AM, Martin Polednik 
wrote:

> On 16/03/17 08:23 +0100, gflwqs gflwqs wrote:
>
>> Hi list!
>> When we upgraded our ovirt environment to 4.1 we get the virtio-scsi
>> interface as default for virtual disks.
>> We have seen a difference in drive order from when we used the virtio
>> interface.
>>
>> Before when we added disks the order of the drives were set by which order
>> the disks was created.
>> So if i had 1 disk as os disk it became vda and added a 50 GB disk that
>> disk became vdb and then added another 8GB disk that became vdc.
>>
>> But now when i add two additional disks with the virtio-scsi interface
>> like
>> the above when i reboot the vm the 50GB disk become sdc and the 8GB disk
>> become sdb even that i created the 50GB disk first?
>> How is the order decided in the virtio-scsi interface?
>> What can i do to ensure that the disks come in the order that i create
>> them?
>>
>> Regards
>> Christian
>>
>
> Could you post the XML (virsh -r list, note the domain
> number and virsh -r dumpxml $domainnumber) before and after adding the
> disks? Need to see whether there are also any iothreads or anything
> else.
>

It doesn't matter - the order of disk discovery on the SCSI bus (by udev?)
is quite random.
You must use /dev/disk/by-id/scsi-...

Y.


>
> Thanks,
> mpolednik
>
>
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>> Users mailing list
>> Users@ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
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> http://lists.ovirt.org/mailman/listinfo/users
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Re: [ovirt-users] virtio-scsi drive order?

[Martin Polednik]

On 16/03/17 08:23 +0100, gflwqs gflwqs wrote:

Hi list!
When we upgraded our ovirt environment to 4.1 we get the virtio-scsi
interface as default for virtual disks.
We have seen a difference in drive order from when we used the virtio
interface.

Before when we added disks the order of the drives were set by which order
the disks was created.
So if i had 1 disk as os disk it became vda and added a 50 GB disk that
disk became vdb and then added another 8GB disk that became vdc.

But now when i add two additional disks with the virtio-scsi interface like
the above when i reboot the vm the 50GB disk become sdc and the 8GB disk
become sdb even that i created the 50GB disk first?
How is the order decided in the virtio-scsi interface?
What can i do to ensure that the disks come in the order that i create them?

Regards
Christian


Could you post the XML (virsh -r list, note the domain
number and virsh -r dumpxml $domainnumber) before and after adding the
disks? Need to see whether there are also any iothreads or anything
else.

Thanks,
mpolednik


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Re: [ovirt-users] virtio-scsi drive order?

[Yaniv Kaul]

On Mar 16, 2017 9:23 AM, "gflwqs gflwqs"  wrote:

Hi list!
When we upgraded our ovirt environment to 4.1 we get the virtio-scsi
interface as default for virtual disks.
We have seen a difference in drive order from when we used the virtio
interface.

Before when we added disks the order of the drives were set by which order
the disks was created.
So if i had 1 disk as os disk it became vda and added a 50 GB disk that
disk became vdb and then added another 8GB disk that became vdc.

But now when i add two additional disks with the virtio-scsi interface like
the above when i reboot the vm the 50GB disk become sdc and the 8GB disk
become sdb even that i created the 50GB disk first?
How is the order decided in the virtio-scsi interface?
What can i do to ensure that the disks come in the order that i create them?


Based on their id on the scsi bus. Use /dev/disk-by-id or so and not sdX
which might change.
Y.


Regards
Christian

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[ovirt-users] virtio-scsi drive order?

[gflwqs gflwqs]

Hi list!
When we upgraded our ovirt environment to 4.1 we get the virtio-scsi
interface as default for virtual disks.
We have seen a difference in drive order from when we used the virtio
interface.

Before when we added disks the order of the drives were set by which order
the disks was created.
So if i had 1 disk as os disk it became vda and added a 50 GB disk that
disk became vdb and then added another 8GB disk that became vdc.

But now when i add two additional disks with the virtio-scsi interface like
the above when i reboot the vm the 50GB disk become sdc and the 8GB disk
become sdb even that i created the 50GB disk first?
How is the order decided in the virtio-scsi interface?
What can i do to ensure that the disks come in the order that i create them?

Regards
Christian
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