To live migrate a powered on Vm we need v motion,there are some prerequisites to be fulfilled before we can achieve migration.
1.) CPU must support v motion,this can be achieved by modifying the CPUID mask at Vm level as follows.
Right click the Vm--edit settings--options--CPUID mask--Advanced.
Virtual Machine Default tab for intel processors and AMD Override tab for AMD processors.
Now change the register values at level 1 and level 80000001.
At level 1 cahnge the ecx value for SSE 4.1 error,For SSE4.2 error change edx value at level 80000001.
For both SSE4.1 and SSE4.2 error, change ecx value at level 1 with ---- ---- 0--0 0--- ---- ---- ---- ----
2.) The host in vsphere HA must not be configured as a failover host.
3.)The VmKernel port of the source machine where vmotion is enabled must have 1000mb so as to fully support vmotion.
4.)The heartbeat datastore must be more than 1.But if its not possible there is a tweak provided in vmware KB VMware KB: HA Error: The number of heartbeat datastores for host is 1, which is less than required: ...