Using virtualization in data centers (DCs), people can run multiple applications independently at a single location, and also can move the virtual machine (VM) to a suitable place. Since a DC carries plentiful applications, its failure would result in service paralysis. To guarantee the service continuity, the relative VMs should migrate from a failed DC to the target backup one. The wavelength division multiplexing (WDM) technology is a promising solution of providing a high-rate and stable inter-DC VM migration trajectory. Thus, to mitigate the service paralysis caused by DC failures, in this paper, we propose an effective parallel inter-DC VM migration framework with the consideration of VM grading, load balancing and elastic optical bandwidth allocation. Compared with previous end-to-end VM migration approach, our method shrinks migration duration exponentially with the higher migration profit and the lower blocking rate. Finally, the simulation results testify these superiorities, and the improvement ratio arrives up to 43%.