[Qemu-devel] Dirty block tracking : External file

[Jd]

Hi
    We are looking for dirty block tracking feature in qemu/kvm for 
implementing more efficient incremental backup. I saw some patches 
around it, but from the conversation could not figure out if it is 
complete or not. If it is complete, can some one point to the branch / 
label from which I can get it.

    Could of questions around the feature.

     * Does this work with qcow format only ? Or for any format ? Can I 
use it with ceph, gluster, etc,,etc.

     * How does dirty block tracking to file get affected by snapshots 
? One would assume that it would mark all the blocks changed since 
tracking begun, irrespective of snapshots pull / rebase....etc. This way 
one might copy more blocks than necessary, but is accurate. And this 
allows the user to do different snapshot operations irrespective of 
backups which is a big thing from users perspective.

Thanks
/Jd