> >> What I am looking for is a stripped down patch series with just a > >> backup block job (no backup archive writer or migration code). That > >> would be easily merged and saves you front rebasing this series as QEMU > changes. > > > > That is Patch 2/6? > > Yes. I sent an RFC series that shows this approach. It is just a prototype > but it > demonstrates that the NBD approach works and performs reasonably well for a > quick Python hack. > > The stripped down patch series needs: > 1. (Optional) query-block virtual_size field if management tool needs to query > drive size 2. Patch 2/6 with review comments addressed 3. 'block-backup' QMP > command (and optionally HMP command) > > That's it!
Thanks. I also have an implementation here using that approach (using nbd.c). The problem is the performance you get. 28% delay is not acceptable. In fact, I want to have the fastest possible solution (additional delay = 0). You want to move the code out of qemu, so that management frameworks can easily plug their own backup tools. That is perfectly valid, but we should do it in a way that does not influence performance. So are there any other ideas?
