VirtIO-FS Is Looking Quite Good For Shared File-System With VMs
Stefan Hajnoczi of Red Hat's virtualization team presented at the FOSDEM 2020 conference last week on this new shared file-system for virtual machines. The VirtIO-FS performance numbers shared during the presentation indeed put it in much better shape than virtio-9p while obviously coming up short of the raw potential offered by virtio-blk. With the DAX mount option for direct access can allow bypassing the guest page cache too for better performance.
While there is Virtiofsd as the default server for exposing directories to a guest, Hajnoczi did raise the possibilities of creating custom servers for backing VirtIO-FS by a distributed storage system, exposing a synthetic file-system from the host, and other possibilities.
Those wanting to learn more about VirtIO-FS can do so via Stefan's slide deck (PDF).