For sure! I would be curious to see the benchmarks. I haven't deployed anything with LVM but I'm surprised that the cost is so high.

There is a pretty thin line between the VM --> Libvirt --> Qemu --> LVM. I would expect the performance to be close to baremetal, but lower of course.

On Thu, Jan 6, 2022 at 6:51 PM Eric K. Miller <emiller@genesishosting.com> wrote:

> Out of curiosity, how are you passing the local storage to the VM? I would also assume a performance hit when using a VM but local storage (instead of Ceph, iscsi, nfs) should still perform well?

We're using and LVM logical volume on 4 x Micron 9300's in a RAID 0 configuration using md. We're using the standard Nova "image_type=lvm" option.

The performance is good, relative to something as slow as Ceph, but the performance hit is pretty significant compared to the host's performance. It is essentially IOPS limited. I can run some tests and provide results if you were interested.

Eric