BTRFS Raid1 with a copy in RAM

Scenario:

  • nspawn container on BTRFS subvolume
  • add btrfs raid1 that’s located in /dev/shm (in RAM)

Question:
Will there be a significant speed improvement to running that nspawn container?

It’s like basically running a container out of RAM, with the benefit of always having a backup of it on drive in case the computer hangs/shuts down. I think there are even OSes that load root into RAM and boot out of that?