I recently brought to life an old PC for testing purposes and I've been playing around with OMV and virtualization.
When installing OMV as VM it shows a much higher cpu usage on the smbd and nfsd when copying files over the (local) network.
- CPU: Intel Core 2 Quad Q9550 (4 cores, supports virtualization)
- RAM: 4GB
- 1 SSD for system
- 2 HDD raid1 (mdadm) for data
- 1 gigabit ethernet port
With OMV installed natively, when transferring a large file from another PC on the LAN to a samba share on OMV, the CPU usage for smbd is about 50%. If using NFS, CPU usage for nfsd is close to 50% as well.
Data transfer rate is about 115-117 MB/s (that's megabytes per second, which is very close to the gigabit ethernet limit).
I then installed Proxmox on the same computer and OMV as a VM. Data HDD's passthrough with virtio-scsi, raid assembled with mdadm on OMV.
All 4 cores and RAM made available for the VM.
Data transfer rate was the same, but CPU usage for smbd was at 100%. Same result with NFS.
I also tried to use OMV as host and OMV on a VM (created using cockpit-machines). Similar results.
My first thought was that cpu virtualization was not being very efficient, but I ran sysbench cpu benchmark on both host and VM with similar results.
Any ideas why this is happening?