I'll take a look -- thanks.
On Tue, Aug 13, 2013 at 4:02 PM, <[email protected]> wrote: > Checkpointing effectively executes a qemu do_savevm function call that > stores everything and anything related to the VM at the current time. To > my knowledge, it IS effectively a standard qemu savevm command that also > has the effect of stopping the VM. You should be able to do a -loadvm to > restore from the checkpoint as desired. > > If all you want to do is guarantee that any disk writes that occur while > qemu is running are partitioned off to a separate entity, qemu-img > provides you with the snapshot facilities to do this: > http://wiki.qemu.org/Documentation/CreateSnapshot > > Regarding how qemu actually stores the differences/images, see: > http://kashyapc.fedorapeople.org/virt/lc-2012/snapshots-handout.html > > Tyler > > > So if I wanted the images to be identical at every boot, would it be > > possible to combine the -snapshot flag with checkpointing? > > > > I guess the part I'm not familiar with is what the checkpoint stores > other > > than the CPU state and the memory state. Does it pull in the qcow deltas > > off the base image since boot up into the snapshot or just leave them in > > the qcow2 image and somehow mark them inside of the actual image? > > > > > > On Tue, Aug 13, 2013 at 9:47 AM, <[email protected]> wrote: > > > >> PS, this is where the qcow extension came from... qemu copy-on-write. > >> :-) > >> > >> > Snapshots take the image at the point of checkpointing and freeze it. > >> Any > >> > further writes to the image are handled using a copy-on-write > >> approach. > >> > > >> > The state of the disk in your example should be nearly identical. The > >> only > >> > thing that should change is system logs and other files that are > >> modified > >> > on every boot. > >> > > >> > Tyler > >> > > >> >> This is probably a silly question since I don't have an in-depth > >> >> knowledge > >> >> of how QEMU checkpoints work, but when I create a checkpoint, is the > >> >> original image changed? I know the qcow2 file is modified, but is the > >> >> actual image content of the non-snapshot portion changed? > >> >> > >> >> In other words, if I boot up a some qcow2 file, call > >> >> checkpoint_and_shutdown() and then boot up the same qcow2 file > >> (without > >> >> any > >> >> -loadvm option) -- is the state of the disk identical between the two > >> >> boots? > >> >> > >> >> Thanks, > >> >> Paul > >> >> _______________________________________________ > >> >> http://www.marss86.org > >> >> Marss86-Devel mailing list > >> >> [email protected] > >> >> https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel > >> >> > >> > > >> > > >> > > >> > _______________________________________________ > >> > http://www.marss86.org > >> > Marss86-Devel mailing list > >> > [email protected] > >> > https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel > >> > > >> > >> > >> > > > >
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