Dealing with domUs state

[Joel Carnat <joel%carnat.net@localhost>]

Hello,

I am running NetBSD 5.0_STABLE/amd64 with xenkernel33-3.3.1nb1.
I have a Windows domU that I'd like to backup from times to times.
In software like VMware or VirtualBox, there is a feature called
"snapshots" which enables to save a full state (memory, disk...) of a
VM. This is a really convinient way to test patches or software.

The only method I found on nbsd/xen was to shutdown the domU, copy the
disk image file and start the domU. When I want to go back to a previous
state, I stop the domU, replace the disk image and start the domU.

Is there some "better" way to deal with domU snapshots ?
Especially ways that would enable to have to domU stil running when
backuping and/or restoring ?

TIA,
     Jo

PS: the domU is hosted on a local FFSv2 partition, with "log" enabled.