[Libguestfs] Possible to speed up guestmount?

Hi, Apparently, guestmount -o allow_other -a "/path/to/raw_file" -m /dev/sda1 "/path/to/mountfolder" is much slower than kpartx -av "/path/to/raw_file" mount /dev/mapper/loop0p1 /path/to/mountfolder (Doing lots of read/write inside the image.) I thought guestmount "only" scripts the above. Seems I was wrong on that. I am currently using libguestfs 1.18.1-1 (because it comes with Debian wheezy/stable) and read the FAQ [1] [2], but still have questions. Seems my version is higher than 1.13.16, so far so good. I am using guestmount inside a virtual machine (to prevent damaging my hosts due to own stuff). It's a sparse raw image (because the tool I am using to create them (grml-debootstrap [3]) can only create raw images). With guestmount, time sudo chroot /path/to/mountfolder sudo -u user echo test takes ~1 second. In comparison, doing the same using kpartx/mount only takes ~0.01 seconds. Converting the image to a metadata preallocated qcow2 image didn't help either. Is there anything I can do to speed up guestmount? Cheers, Patrick [1] http://libguestfs.org/guestfs-faq.1.html#upload-or-write-seem-very-slow [2] http://libguestfs.org/guestfs-performance.1.html [3] http://grml.org/grml-debootstrap/