Servers can be configured with either single or dual redundant power supplies. Traditional workloads normally demand dual power supplies to protect against downtime in the case of a power supply or feed failure. If your Ceph cluster is large enough, then you may be able to look into the possibility of running single PSUs in your OSD nodes and allow Ceph to provide the availability in case of a power failure. Consideration should be given to the benefits of running a single power supply versus the worst case situation where an entire feed goes offline at DC.