Awesome, looking forward to it. I may be misunderstanding what's happening under the hood, but at least for me, calling 'loadvm' on a single snapshot over and over seems to work the first few times and then immediately blue screens the WinXP guest with PFN_LIST_CORRUPT. I was under the assumption that all runtime modifications were being written back to the image, effectively "corrupting" something (whether it was changes to the snapshot or the "backing image" causing things to break).
Until then, I've seemed to have found a workaround for the feature itself. Instead of creating a snapshot with 'savevm', I can start the VM with -snapshot and then call: migrate "exec: gzip -c > snapshot.gz" in QMP and it saves the live image to a compressed file. Make sure it's completed migration before exiting with "info migrate". Subsequently loading the snapshot with: qemu-* <whatever flags> -incoming "exec: gzip -c -d snapshot.gz" -snapshot will load the live snapshot and redirect all runtime modifications to a temp file. http://www.linux-kvm.org/page/Migration says not to use -snapshot, but who follows the rules anyways? ;) It seems to work so far and things haven't exploded yet. Running md5sum on the qcow2 image and gzip snapshot before and after shows no changes to either files. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1184089 Title: [Feature request] loadvm snapshot as read-only Status in QEMU: New Bug description: There are many ways to take and manage snapshots in QEMU, but one main feature that's missing is the ability to 'loadvm' a LIVE snapshot and have all future changes redirected to a temporary file. This would effectively be combining the -loadvm and -snapshot switches and make the snapshot read-only. With this feature, users would be provided a "sandbox" and be able to start and restart the same live snapshot without corrupting the image in doing so. I found a lot of discussion about this topic on the mailing list years ago, including some patch submissions, but none of the conversations panned out. http://lists.gnu.org/archive/html/qemu-discuss/2011-10/msg00011.html http://copilotco.com/mail-archives/qemu.2008/msg00072.html http://web.archiveorange.com/archive/v/1XS1vcusGInZKG2e0ImX http://marc.info/?l=qemu-devel&m=117191084713590 What would it take for this feature to be added, and can we use the patches submitted by Eddie Kohler to enable this feature? To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1184089/+subscriptions
