On Wed, Apr 7, 2021 at 9:07 AM Daniel P. Berrangé <berrange@xxxxxxxxxx> wrote: > > On Wed, Apr 07, 2021 at 07:45:47AM -0700, Dariusz Smigiel wrote: > > Hi Team, > > > > I need to migrate beefy instance between two different hosts which is > > running out of resources. > > > > I was wondering, if there is a way to change maximum memory value during > > live migration, without shutting down the instance. > > The maximum memory value controls the RAM mapping exposed to the guest, > and as such is part of the guest ABI. Guest ABI is never permitted > to change during a live migration, as that will almost always have > seriously bad effects on the guest OS, and possibly the QEMU migration > data stream format. > > IOW, no, you can't change max memory during migration, only a cold > boot. Thanks, That explains a lot. > > Libvirt will enforces that preservation of ABI during migration by > validating the 2 XML configs for the src+dst host, and only permits > changes to the backend host OS integration, never frontend. > > > Regards, > Daniel Best regards, Dariusz
