vCenter’s Distributed Resource Scheduler (DRS) is by far one of my favorite features of VI2.5. Distributed Power Management (DPM) is an experimental extension of DRS that will power down unneeded hosts, and wake them when needed again. How cool it that! The good news is, it works great. The bad news is, in the current release there is a bit of a bug in DPM.
When vCenter is restarted it looses track of any hosts that it (DPM), or you (the VI admin) have put in a suspended state. The suspended hosts show up in VC as “NotResponding”, and VC is no longer capable of waking them up. The fix is to manually power them on… how aggravating. I finally had some free time this morning so I threw together a quick PowerShell script to bridge the gap until VMware releases a production ready version of DPM.