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.