[PVE-User] live migration amd - intel
lists at merit.unu.edu
Thu Feb 27 11:09:07 CET 2020
Thanks for your reply!
On 2/26/20 4:14 PM, Stefan Reiter wrote:
> On 2/26/20 3:35 PM, mj wrote:
>> Just to make sure I understand something. We have an identical
>> three-node hyperconverged pve cluster, on Intel Xeon CPU's.
>> Now we would like to expand, and we are investigating what path to
>> The way we understand it is: if we would like to do live migrations
>> between pve hosts, the servers need to have similar CPUs, or otherwise
>> we need to virtualise the CPU as well. (so set CPU type to kvm64)
> Note that even kvm64 does not really work for cross-vendor
> live-migrations (i.e. AMD <-> Intel as mentioned in subject). This was
> recently discussed on the pve-devel list , as well as an older bug
> report .
>  https://pve.proxmox.com/pipermail/pve-devel/2020-February/041750.html
>  https://bugzilla.proxmox.com/show_bug.cgi?id=1660
>> In case it matters: 90% of our VMs are debian 9/10 hosts.
>> While we could do change to kvm64, we currently use cpu type 'host',
>> and we wonder how much performance kvm64 would cost us, and what
>> potential other drawbacks this could have.
> Aside from the above, the performance impact of switching to kvm64 is
> largely dependent on the software you are running within your VM. Raw
> CPU performance will stay the same, but most hardware acceleration (e.g.
> AES for encryption or AVX) will not be available to the guest.
> If the CPUs are from the same vendor, you can most likely enable the
> older generation CPU type for your VMs and still get away with
> live-migration. This way you can use _most_ acceleration features, and
> are just missing out on any new ones introduced in the newer CPU gen.
>> Has anyone ever done much testing on this subject? Anyone with
>> interesting insights / knowledge / experiences to share on this subject?
> Hope that helps,
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