How to configure VirtIO FS for Proxmox VE

Create /var/lib/vz/snippets/exec-cmds with the following contents:

#!/bin/bash
VMID="$1"ACTION="$2"SLEPT=""
vmpid() {  cat "/var/run/qemu-server/$VMID.pid"}
if_action() {  if [[ "$ACTION" == "$1" ]]; then    shift    eval "$@"  fi}
sleep_once() {  if [[ -z "$SLEPT" ]]; then    sleep 1s    SLEPT=1  fi}
exec_virtiofsd() {  echo "Needs virtiofsd for directory $1"  /usr/lib/kvm/virtiofsd --socket-path=/run/qemu-server/$VMID-${1/\//}.virtiofsd -o source=$1 -o cache=always --daemonize > /dev/null 2>&1 &}
exec_cmds() {  while read CMD ARG1 ARG2 REST; do    case "$CMD" in      "#virtiofsd")        if_action pre-start exec_virtiofsd "$ARG1"        ;;
    esac  done}
exec_cmds < "/etc/pve/qemu-server/$1.conf"
exit 0

Add a comment to the top of the config to each VM that needs it under /etc/pve/qemu-server/<VMID>.conf. It denotes the directory from the local machine to share.

#virtiofsd /media

args: -chardev socket,id=char0,path=/run/qemu-server/101-media.virtiofsd -device vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=/media -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on -numa node,memdev=mem
# path=/run/qemu-server/101-media.virtiofsd -- '101' should be changed to match the VMID and 'media' should be changed to match the shared directory name without slashes.# size=4G -- should be changed to be equal to the VM's RAM size# tag=/media  -- this is used by the VM to mount the correct virtiofs share

Once your VM is booted up, you can test the directory mount with:

mkdir /mnt/tmpmount -t virtiofs /media /mnt/tmp