Re: [libvirt] with latest libvirt(from git) on F18, time to take internal snapshot increases as snapshot count rises

On 10/05/2012 11:00 AM, Kashyap Chamarthy wrote: Internal snapshots: pro - single file holds everything, so move that file, and you've moved the snapshot con - qemu doesn't test it very much, and it shows, with poor performance con - the guest is paused for seconds or even minutes while taking the snapshot con - there is no way to access the data at the time of the snapshot while qemu is running (although this feature has been requested of qemu, no one has yet indicated that they plan to implement it any time soon) External snapshots: pro - you can do read-only operations on the data at the time of the snapshot even while qemu continues to run pro - currently very well tested, and qemu continues to enhance what is supported pro - the guest is paused for less than a second while taking the snapshot con - you now have multiple files to track, so tasks like reverting and cloning become more difficult to conceptually manage (but even here, libvirt is trying to add code to eventually get to the point where we can guarantee that any commit, pull, revert, or other snapshot operation on one file managed by libvirt will be prevented if any other file would be corrupted by the change, rather than the current state of things of letting you shoot yourself in the foot) Both are useful, and the end goal is to have libvirt expose both options as well as document some of the tradeoffs so that you can use the method best suited for your needs. -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org