Abstract: Migration of a virtual machine from a source host computing system to a target host computing system in a context in which a centralized portion of virtual machine state is maintained in a storage that is accessible to both the source host computing system and the target host computing system, and a localized portion of the virtual machine state is maintained in local storage of the source host computing system. For instance, the centralized portion of the virtual machine state might be user data, and the localized portion might be backing files for the virtual machine. In order to support the potential migration, at least a portion of the localized portion of the virtual machine state are backed up to a storage that is accessible to both the source and target host computing systems.

Abstract: Allocation of software and data support resources for a virtual machine between a physical support environment and an external location, and migration of a virtual machine between physical support environments. Prior to migration, the virtual machine operates on the first physical support environment using a resident portion of the support resources that is resident on the first physical support environment, and an external portion of the support resources that is not resident on the first physical support environment. The virtual machine is then migrated to a second physical support environment that either already has access to or at least has the capability of accessing a copy of the resident support resources. This migration may be accomplished by mapping a copy of the resident support resources on the second physical support environment to a copy of the external support resources. This allows migration without contemporaneously copying the external portion.