Re: Issue with QEMU Live Migration

[Prasad Pandit]

On Sun, 25 Aug 2024 at 22:40, Arisetty, Chakri <carisett@akamai.com> wrote:
> > - start the mirror job
> > - qmp_migrate
> > - once PRE_SWITCHOVER is reached, issue block-job-cancel
> > - qmp_migrate_continue
>
> We use exact same steps to do live migration. I repeated the test now
>
> Sure, as you suggested to rule out any incorrect usage, I repeated the test 
> with above steps.
> once RAM migration state moved to pre-switchover, issued block-job-cancel. 
> There are no more dirty blocks.
> But all the disk writes from 'pre-switchover' state to 'complete' state are 
> lost.
> Thus, it is creating loss of customer data.
>

* How is 'issue block-job-cancel' command issued exactly at the
PRE_SWITCHOVER stage? virsh blockjob --abort?

* Recently a postcopy issue, wherein the migrated guest on the
destination machine hangs sometimes with migrate-postcopy but not with
virsh ---postcopy-after-precopy. It seems virsh(1) handles the switch
better. Wondering if it's similar with 'block-job-cancel'.

Thank you.
---
  - Prasad