Re: [Libguestfs] getting guestfs_rsync_out to work
On Sun, Feb 08, 2015 at 12:11:37PM -0600, Jeff Brower wrote:
With continuous loop testing, what we found is that we have to shut
down and re-launch the image handle to see changes on the Win7 live
guest. Unfortunately image re-launch takes time, 3-5 sec (the image
size is 50 GByte). I'm assuming this is because libguestfs makes an
internal copy of filesystem, and works from that, and doesn't
"refresh" this internal copy until re-launching the image handle.
This isn't surprising. Libguestfs doesn't make an internal copy of
the whole filesystem, but the libguestfs appliance will have a copy
(in its kernel memory) of any parts of the disk that rsync read.
See also:
http://libguestfs.org/guestfs.3.html#architecture
Could we create a second partition on the guest that is much
smaller, say 50 MByte, attach the image to that, and thus reduce the
shutdown and re-launch time into the msec range? Is there another
real-time method, not using rsync?
The time to relaunch the appliance doesn't depend on the size of the
disk.
You could try hotplugging but it may not be much faster:
http://libguestfs.org/guestfs.3.html#hotplugging
I think what you really need to do is to install a backup agent in the
Windows guest and use a regular network backup.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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