Hi there!
I faced a problem with slow disk speed performance inside a VM (when a VM has a disk on host NVMe SSD).
For instance, when I copy 10GB file from one pve to another pve (LAN 10Gbit/s):
rsync -P -avz file10G 10.1.123.1:
sending incremental file list
file10G
10,737,418,240 100%...