Large VMs on Proxmox

[Babetecno]

Hi,

I have a Proxmox server with 128GB and two sockets (8C/16T, 64 GB each). When I create a Windows Server VM with 64GB and 2 sockets with 8 vCPU per socket, the performance of the VM is not good enoough. When I decrement the RAM of the VM to 32 GB, the performance is good. NUMA option on the VM is enabled. Why is this happening? Is this a KVM problem?

I guess that when I assign a quantity of RAM equal or larger than the RAM in one socket of the server, Proxmox needs to retrieve RAM memory from the other processor, decrementing the performance. Am I right?

Is there anyway to create Large VMs on Proxmox with a good performance?

Thanks.

Best R.

 

[oguz]

hi,

* could you send the VM configuration? qm config VMID

the performance of the VM is not good enoough.

what do you mean exactly? can you give a specific example?

it can be happening for many reasons, like for example the PVE host could be running out of resources if the VM is eating too much.

 

[Babetecno]

root@pve1:~# qm config 101 agent: 1 bootdisk: scsi0 cores: 4 cpu: host ide0: none,media=cdrom memory: 65536 name: WS2k16-APP net0: virtio=DA:05:CE:AA:21:1F,bridge=vmbr10,firewall=1 numa: 1 onboot: 1 ostype: win10 scsi0: RAID1SSD:101/vm-101-disk-0.raw,cache=writeback,discard=on,size=200G scsihw: virtio-scsi-pci smbios1: uuid=bdbaa789-5adc-4492-8841-4747dd199b82 sockets: 2 vmgenid: 5eb12257-4ca9-47c3-9556-86ef3789e7aa


The "normal" use of the VM is slow considering the virtual hardware specs. It takes too much time to open
a folder, to open PowerShell, to open a Program... Nothing exagerate but too much for the associated hardware.

Thanks.