I didn't mean to imply that post-copy always results in data loss. But this is possible if the network connection between source and destination host is disconnected during the post-copy operation. Am Mo., 18. Sept. 2023 um 12:14 Uhr schrieb Michel Jouvin <michel.jouvin@ijclab.in2p3.fr>:
Hi,
post-copy looks to meas a very attractive approach for these heavy-loaded VMs but I didn't understand that there is an inherent risk of data-loss (except if there is an implementation bug)... Are you sure?
Michel
Le 18/09/2023 à 11:29, Rafa a écrit :
As I can read and understand from the source compute logs, the memory is copied over successfully and there is no migration timeout. But after the instance is paused there is something wrong happening. I first thought it could be the short migration downtime (default=500ms), that's why I increased the "live_migration_downtime" to higher values (max was 300000ms; just for testing:) ) and nothing changed.
And the error message doesn't say much either.
I don't really want to use post-copy as it can lead to data loss.
Auto Converge doesn't seem to help either.
Am Fr., 15. Sept. 2023 um 13:56 Uhr schrieb <smooney@redhat.com>:
On Thu, 2023-09-14 at 19:07 +0200, Rafa wrote:
Hi, could you share logs from the target compute node as well? yes, here: https://paste.openstack.org/show/blpJE8krA1N6PVaLTVF0/
if the vm is under heavy memory load then its advisable ot use post-copy live migration.
in general live migration is not intened to be used with a vm under load as there is no gurenettee that it will ever complete. post-copy live migration can signifcantly increae the probablity that a vm under load will live migrate in a reasonabel amount of time.
https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.liv...
auto converge can also help but tis less important
https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.liv...