Windows Server 2008 R2 has a feature called “Live Migration” as well as new Cluster Shared Volumes (CSV) feature. However, there’re enough of issues now where Live Migration is failing. Its important to note that there’s information available on TechNet site that discusses Live Migration and CSV, and also includes some troubleshooting information. Please note, that issues that prevent Live Migration from succeeding have to do with proper network configuration. In this post, we’ll address the main network related configuration items that need to be reviewed in order to be sure Live Migration has best chance of succeeding. We begin with an initial set of assumptions which include the R2 Hyper-V Failover Cluster has been properly configured and all validation tests have passed without failure, highly available VMs have been created using cluster shared storage, and virtual machine(s) are able to start on at least one node in the cluster.
Full Article: Core team blog