New Server with Intel Xeon Gold 6240 migration problem

[Thomas Plant]

Hi,

we have added a new server to our cluster. When we try to migrate a VM from the old (Intel Xeon 5120) to the new server (Xeon 6240) we get the following error:

020-11-16 10:08:32 starting migration of VM 175 to node 'pve8' (10.10.2.94)
2020-11-16 10:08:33 starting VM 175 on remote node 'pve8'
2020-11-16 10:08:34 [pve8] kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
2020-11-16 10:08:34 [pve8] kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11]
2020-11-16 10:08:34 [pve8] kvm: Host doesn't support requested features

With a little googling I found that it is a disabled feature of the cpu (TSX), which should be the culprit. In fact when I start a VM with 'Broadwell-noTSX' I can migrate without problems.

Is it possible to reenable on the new server the TSX feature? If not we have to shut down and start all our customer VMs with the 'broadwell-noTSX' CPU setting.

Thanks,
Thomas

 

[mira]

Live migration is only reliable when using the same CPU on all nodes in the cluster. For compatibility you should use the default CPU type (kvm64), but there's still no guarantee between different CPUs.
Please post the VM config (qm config 175).

 

[Thomas Plant]

Hi, here is the config of the VM:

root@pve4:~# qm config 175
agent: 1
bootdisk: scsi0
cores: 2
cpu: Broadwell
description: CentOS Template no Software%0ARepos MariaDB/PHP/CodeIT aktiviert.%0A%0ALetztes Update%3A 27.05.2020 17%3A30
ide2: NFS2:iso/CentOS-7-x86_64-Minimal-1908.iso,media=cdrom
memory: 4096
name: CentOS-7-Template-Leer
net0: virtio=D6:1F:66:7C:46:8B,bridge=vmbr0
net1: virtio=2E:F1:70:6D:31:51,bridge=vmbr1
numa: 0
onboot: 1
ostype: l26
scsi0: NFS01:175/vm-175-disk-0.qcow2,discard=on,size=32G
scsihw: virtio-scsi-pci
smbios1: uuid=8ee966be-5ada-4f32-a351-8faafbc1b606
sockets: 1
vmgenid: 6f63fa88-8ad7-4fbf-97b7-cb408c11089e

When booting the host I modified the kernel boot parameters, added 'tsx=on' and now live migration works....