Ivan has a nice article about vMotion:
- Virtual Machines are in the order of GBs and moving them is not a simple operation. Across WAN this is significant traffic
- The requirement of retaining the sessions mandates the VM to retain the IP address even after movement. The traditional way to handle that is to still keep it in the same VLAN domain “under a router”.
- All switches under the router will have to be part of all VLANs
- The VLAN configuration have to be synchronized on all the servers and switches. How much of this config problem is solved by overlays
- VM’s communication with other services will not change – it will continue to flow and now the paths may be longer.