[Unit]
Description=Mount backup rootfs
After=network.target
After=virtiofs_internal.service

[Service]
Type=oneshot
User=root
Group=root
ExecStart=/bin/bash -c '[ -e "/dev/vdb" ] && (mkdir -p /mnt/backup; chown 1000:100 /mnt/backup; mount /dev/vdb /mnt/backup) || (rm -rf /mnt/backup)'
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target