Recently I’ve been doing a lot of work with HyperV clustering, new HP DL380 G7 servers, and Netapp storage. One of the great features I’ve uncovered is the sweetness dynamic memory adds when doing live migrations. If you are not sure what Dynamic memory is you can have a read here.
Essentially when doing a HyperV Live Migration with Dynamic memory enabled on the virtual machine, the migration process only has to copy the USED memory pages to the other host. So if you virtual machine has 512MB startup and maximum 4096MB memory configured and is using 640MB of memory, it will only have to Live Migrate 640MB.
This means the Live Migration process is super quick and over a 1GB Live Migration network I have seen 10 sec live migrations occur regularly.