- Windows Server 2008 R2 support a feature called ‘Live Migration’, said one of my students.
1. The source node makes a connection (TCP) with the destination node to transfer the VM configuration data. A ‘copy’ of the VM is created on node 2 and memory is allocated.
2. Memory is transferred from source node to destination node. The memory copies over the network, and the migrating VM continues to run.
3. A final memory copy process copies the remaining modified memory pages to the destination node. In this stage the network between source and destination is critical to the speed of the live migration. (1GB is recommended) Also, if the VM is heavily accessed under the live migration, that might affect the speed as well.
4. Move the ‘storage’ from source node to destination node (.vhd files, pass-through disks)
5. The VM is online on the destination node since it now has the updated working set and access to the VM storage.
6. Time to cleanup! A message is sent to the physical network switch telling him to re-learn the MAC address of the migrated VM. Now the VM can use the correct switch port.
The benefits this feature gives us, is that it provides us with the opportunity to build a dynamic datacenter, easier maintenance of the nodes, and a hot topic in these days: green IT