[ovirt-users] Mixing CPU types

[Matthew Trent]

?Actually it works great! It's been supported by KVM for a while now. I had one Proxmox cluster with a mix of AMD and Intel and migrated KVM VM's between them frequently. OpenStack (KVM) and VMWare support this as well.


The trick is to expose a virtual CPU with a common set of features to the VMs. KVM handles the rest. From the KVM FAQ:

http://www.linux-kvm.org/page/FAQ#Does_KVM_support_live_migration_from_an_AMD_host_to_an_Intel_host_and_back.3F


"Does KVM support live migration from an AMD host to an Intel host and back?


Yes. There may be issues on 32-bit Intel hosts which don't support NX (or XD), but for 64-bit hosts back and forth migration should work well. Migration of 32-bit guests should work between 32-bit hosts and 64-bit hosts. If one of your hosts does not support NX, you may consider disabling NX when starting the guest on a NX-capable system. You can do it by passing "-cpu qemu64,-nx" parameter to the guest."

--
Matthew Trent
Network Engineer
Lewis County IT Services
360.740.1247 - Helpdesk
360.740.3343 - Direct line
________________________________
From: Yaniv Kaul <ykaul at redhat.com>
Sent: Tuesday, February 2, 2016 2:17 PM
To: Matthew Trent
Cc: users at ovirt.org
Subject: Re: [ovirt-users] Mixing CPU types



On Mon, Feb 1, 2016 at 9:13 PM, Matthew Trent <Matthew.Trent at lewiscountywa.gov<mailto:Matthew.Trent at lewiscountywa.gov>> wrote:
Though our new oVirt setup is better in most ways, cross-CPU-type migration is one of the features I miss from Proxmox. KVM supports mixed-CPU migration for a while now, even between AMD and Intel.

http://www.linux-kvm.org/page/Migration

I highly doubt the above works in real life scenarios.
Y.



I'm using a bunch of re-purposed servers with a mix of AMD and Intel. I separate them into clusters, as noted, but it sure would be nice to be able to live migrate between them. :)

--
Matthew Trent
Network Engineer
Lewis County IT Services

> Hi Rene,
>
> Thank you very much for coming back to me.
>
> That's perfect then and answers my questions exactly.
>
> Much appreciated.
>
> Regards.
>
>Neil Wilson.
>
>
>On Wed, Jan 27, 2016 at 1:57 PM, René Koch <rkoch at rk-it.at<http://rk-it.at>> wrote:
>>
>> Hi Neil,
>>
>> You can mix cpu types (but not AMD and Intel) if you leave the cluster
>> level at the lowest cpu level.
>> I personally don't mix cpu levels if possible, but instead create own
>> clusters for each cpu type in order to be able to use the newest cpu
>> features...
>>
>>
>> Regards,
>> René
>>
>>
>> On 01/27/2016 12:53 PM, Neil wrote:
>>
>> Hi guys,
>>
>> I currently have an oVirt 3.5 cluster with Sandy Bridge Xeon CPU's, and I
>> need to add a new host for more RAM and vCPU's, however the new Xeon e5
>> cpu's are Haswell based.
>>
>> Can I mix CPU types (Haswell and Sandy Bridge) in my cluster and will I be
>> able to migrate between my hosts?
>>
>> I'm guessing that for this to work I'll need to leave my "CPU type" set to
>> Sandy Bridge, will the Haswell based CPU be compatible with my cluster, but
>> just run without any Haswell type features?
>>
>> Apologies if this is a dumb question or if it's been answered before.
>>
>> Thank you.
>>
>> Regards.
>>
>> Neil Wilson
>>
_______________________________________________
Users mailing list
Users at ovirt.org<mailto:Users at ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20160203/5c0097cf/attachment-0001.html>