21:51 < foxx> hello! does anyone know if libguestfs supports any sort
of COW (copy on write) functionality? for example, if i
mount an image which is RO, can i make it write any
changes out to a higher dir (such as how overlayfs/aufs
works)
The answer is yes. Create a qcow2 overlay on top of your
image before starting:
qemu-img create -b original.img -f qcow2 overlay.qcow2
guestfish -a overlay.qcow2
[etc]
Changes are written to overlay.qcow2. The original is not modified.
You can also display differences between the overlay and the original
using 'virt-diff':
http://libguestfs.org/virt-diff.1.html
https://rwmj.wordpress.com/2013/12/19/new-in-virt-tools-virt-diff/#content
Rich.
--
Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW