----- Original Message ----- > From: "Shu Ming" <shum...@linux.vnet.ibm.com> > To: "Federico Simoncelli" <fsimo...@redhat.com> > Cc: "VDSM Project Development" <vdsm-devel@lists.fedorahosted.org> > Sent: Tuesday, February 7, 2012 4:00:39 PM > Subject: Re: [vdsm] Live Merge and Storage Live Migration > > Another question about the Storage Live Migration wiki page, in the > Engine-VDSM flow: > > createVolumeCrossSD(): > domain1: [base(raw)]<-[snap1(qcow2)]<-+-(VM) > domain2: +-[snap2(qcow2)] > > > blockMigrate(): > domain1: [base(raw)]<-[snap1(qcow2)]<-+ > domain2: +-[snap2(qcow2)]<-(VM) > > > I think there must have a storage quiesce time between the snap2 > creation and setting the VM on top of snap2. > When the snap2 is being created, VM cannot access snap1. Only after > VM is set on top of snap2, the quiesce period is end.
That is not required. The snap2 is there as place-holder (it doesn't hold any internal state about snap1). We need to do so because the lvm volume must be created on the SPM. After that the qemu-kvm re-initialize the qcow header in snap2 (hopefully fixing BZ#785683 too). -- Federico _______________________________________________ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
