Re: More work on Livebackup for qemu/qemu-kvm

[shu ming <shuming@linux.vnet.ibm.com>]

Jagane,
   we are testing and reviewing the livebackup workspace from
     git://github.com/jagane/qemu-livebackup.git

  Several questions are coming from us.
  1)  It seems that the workspace has not been updated for a while.  Is 
there any new update for this project?
   2)  It looks like that the support is hightly bounded with qcow2 
image format.  Is there any plan to support
       other formats? Like raw, qed streaming?
   3) Can we add some checksum method to check if the backup image is 
correct in the process of image
        transfering?  For example, a checksum is made before the 
snapshot is transfered and then is compared
        with the checksum of the backup image after the backup is done.

Jagane Sundar:
> Hello All,
>
> I have made more progress on the proposed Livebackup feature
> for qemu and qemu-kvm.
>
> Based on Jes' feedback, I have switched over to using command
> line parameters instead of specific named files. So, a typical
> command line looks like this:
>
> # ./x86_64-softmmu/qemu-system-x86_64 -drive \
> file=/dev/kvm_vol_group/kvm_root_part,boot=on,if=virtio,livebackup=on \
> -drive file=/dev/kvm_vol_group/kvm_disk1,if=virtio,livebackup=on \
> -m 512 -net nic,model=virtio,macaddr=52:54:00:00:00:01 \
> -net tap,ifname=tap0,script=no,downscript=no \
> -vnc 0.0.0.0:1000 -usb -usbdevice tablet \
> -livebackup_dir /root/kvm/livebackup -livebackup_port 7900
>
> Note the new option livebackup=on in the drive parameters, and
> the two new parameters -livebackup_dir and -livebackup_port
>
> Here's my strategy for rigorous testing of this new code:
> I have created two virtual disks in LVM logical volumes, and
> added code in qemu livebackup to create a LVM snapshot as
> soon as livebackup_client connects to qemu and creates a
> livebackup snapshot. Then I binary compare the livebackup
> backed up version of the virtual disk image with the
> LVM snapshot that was created by using 'cmp'.
> The backup images are a bit for bit match!
>
> As always, all information is available at:
>
> http://wiki.qemu.org/Features/Livebackup
>
> I have also sent in my application to make a presentation at
> the qemu forum 2011.
>
> In the meantime, I invite feedback on livebackup.
> Specifically, I am interested in scrutiny of my testing
> methodology.
>
> Also, I plan to add encryption (probably SSL) to the
> livebackup TCP connection, and some form of authentication.
>
> Any thoughts, feedback?
>
> Thanks,
> Jagane
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