How to disable rsync compression for "lxc copy"? 100% cpu and slow for local network transfer

@stgraber I tried to overmount as you described. The overmount works but lxc copy (snapd lxd) would fail instantly complaining about missing linked libraries. It appears snap running a non-snap rsync breaks library links since it can’t find them in the snaps env.

Pretty much isolated glass ceiling of lxc copy to rsync and I just need a fast way to verify it.

  1. Ubuntu 22.04
  2. 5.19 custom kernel
  3. MTU 9000
  4. iperf3 verified 37Gb/s bidirectional over 40G nic.
  5. fio verified 1000MB+ read/write speed on local pcie4 nvme.
  6. Snapd lxd latest stable
  7. rsync.compression off in lxc storage
  8. amd zen3 cpu

Even with above config, lxc copy between the two machines, large database files, can only muster 3Gb/s max transfer speed or around 375MB/s

What is the easiest way for me to inject a distro default (optimzied) rsync into lxd for testing? I can compile lxd if needs be.

Thanks.