Re: [libvirt] VN-Link vNIC memory state copying on VM Migration

> OK. In phase 3, the RAM used by VM in source host is copied to the > destination. Then what about the memory state of vNIC's in the M81KR VIC. > Isn't there any memory for traffic passing through vNICs and also for > vNIC statistics?  What I am talking about is copying of this memory to the > destination vNIC. No, that data (statistics, etc) are not copied to the dst host/vnic. However, you can find those statistics/counters on the switch (which are preserved across live migrations).

Thanks /Chris > > (*) See the migration parameter 'migrate-setmaxdowntime' > > > > In phase 4 libvirt applies the port profile to the interfaces > > that need it and starts the VM (which had been created and put in > > pause state in phase 2). > > There is therefore a small period during which both VMs (the one > > on the source host and the one on the destination host) are in pause > > state (see dotted lines above). > > Phase 4 will start the VM on the dst host, > > Phase 5 will kill the (paused) VM on the src host. > > > > The amount of time during which both VMs are in pause state depends on > > a number of factors, including: > > - maxdowntime:  the smaller you configure this value and > >                - the longer will take the migration to complete, but > >                - the smaller the pause duration will be > > - bandwidth available on the interface/s used to carry the migration > >  traffic, and amount of RAM assigned to the VM (since you need to > >  copy it) > > - time taken to complete the port profile associations on the dst host > >  (which depends on how loaded the switches are) > > - ... > > > > > > Hope this clarifies a bit. > > /Chris > > > >> If this memory state (or traffic) is not copied and moved to the > >> destination vNIC how the smooth communication, which is > >> guaranteed on VM migration, is achieved? > >> > >> Thanks > >> Jagath > >> > >> > > >> > If you refer to port profile info, then there is no copying involved: > >> >  the source host disassociates the vnic port profile and > >> >  the destination host re-associates the port profile on the new vnic. > >> > > >> > /Chris > >> > > >> >> -----Original Message----- > >> >> From: libvir-list-bounces(a)redhat.com > >> > [mailto:libvir-list-bounces@redhat.com] On Behalf Of Jagath > >> >> Weerasinghe > >> >> Sent: Friday, April 13, 2012 9:16 AM > >> >> To: libvir-list(a)redhat.com > >> >> Subject: [libvirt] VN-Link vNIC memory state copying on VM Migration > >> >> > >> >> Hi All, > >> >> > >> >> I am new to libvirt. And want to know how the VM migration > >> >> occurs in VN-Link (IEEE802.1Qbh). As far as I know, > >> >> the memory state of vNICs in M81KR VIC has to be copied > >> >> and moved to the destination vNIC on VM migration. > >> >> Is that correct? If so, could you please tell me how this > >> >> has been implemented in libvirt? > >> >> > >> >> Thanks > >> >> Jagath > >> >> > >> >> -- > >> >> libvir-list mailing list > >> >> libvir-list(a)redhat.com > >> >> https://www.redhat.com/mailman/listinfo/libvir-list > >> > >> -- > >> libvir-list mailing list > >> libvir-list(a)redhat.com > >> https://www.redhat.com/mailman/listinfo/libvir-list