On 04/03/2018 07:01 AM, Nikolay Shirokovskiy wrote:
Hi, all.
This is another RFC on pull backup API. This API provides means to read domain disks in a snapshotted state so that client can back them up as well as means to write domain disks to revert them to backed up state. The previous version of RFC is [1]. I'll also describe the API implementation details to shed light on misc qemu dirty bitmap commands usage.
Thanks for such a detailed message! It's got enough that I want to spend some time thinking about the implications, but this is an early reply to let you know I'm at least working on it now. The first thing that caught my eye:
Here is a list of bitmap commands used in implementation but not yet in upstream (AFAIK).
x-vz-block-dirty-bitmap-remove x-vz-block-dirty-bitmap-merge x-vz-block-dirty-bitmap-disable x-vz-block-dirty-bitmap-enable (not in the examples; used when removing most recent checkpoint) x-vz-nbd-server-add-bitmap
How close are we to having upstream implementations of any of those commands? If not, what are their specifications? Libvirt is very hesitant to add code that depends on a qemu x-* command, but if we can get the actual command into qemu.git without the x-* prefix, it is easier to justify libvirt adding the API even if qemu 2.13 is not yet released. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org