Hi all,
first let me thank all involved for the excellent software that is Proxmox - it's an wonderful implementation of various VM technologies and very useful to me in my homelab. Now my question; I am wanting to set up a host with various vms that provide networked compute capacity, among others this includes OpenFOAM CFD compute VMs. OpenFOAM is famously memory-bandwidth limited and I am running into a situation where LXC runs at near-bare-metal speeds (just a few % off), but the exact same software installed in a KVM VM will lose enormous amounts of performance. The main two CPU intensive tasks in CFD are meshing and the sim itself, with runtimes as follows:
There must be something simple I'm missing here - ESXi 7.0 will run both meshing and sim in similar times as the LXC runtimes on the same hardware with identical BIOS settings...
This is on a 4-socket HPE DL560 Gen8 with 2 sockets populated (E5-2690 v2) with 16 sticks of 2R 1866 DDR3.
As I am new to Proxmox but not ESXi, any help and pointers to get similar performance to ESXi would be *much* appreciated!
Kailee.
PS: Some more details; LXC was privileged because need to mount nfs, kvm had ubuntu 20.04 installed, NUMA was activated.
first let me thank all involved for the excellent software that is Proxmox - it's an wonderful implementation of various VM technologies and very useful to me in my homelab. Now my question; I am wanting to set up a host with various vms that provide networked compute capacity, among others this includes OpenFOAM CFD compute VMs. OpenFOAM is famously memory-bandwidth limited and I am running into a situation where LXC runs at near-bare-metal speeds (just a few % off), but the exact same software installed in a KVM VM will lose enormous amounts of performance. The main two CPU intensive tasks in CFD are meshing and the sim itself, with runtimes as follows:
| Bare Metal | LXC | KVM | ESXi 7.0 | |
| meshing (s) | 230 | 247 | 365 | 245 |
| sim (s) | 95 | 96 | 222 | 96 |
There must be something simple I'm missing here - ESXi 7.0 will run both meshing and sim in similar times as the LXC runtimes on the same hardware with identical BIOS settings...
This is on a 4-socket HPE DL560 Gen8 with 2 sockets populated (E5-2690 v2) with 16 sticks of 2R 1866 DDR3.
As I am new to Proxmox but not ESXi, any help and pointers to get similar performance to ESXi would be *much* appreciated!
Kailee.
PS: Some more details; LXC was privileged because need to mount nfs, kvm had ubuntu 20.04 installed, NUMA was activated.
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