HP SL6000 - Manual (Page 19)

Full AC or DC redundancy requires two power supplies to run the z6000 chassis. If one power supply
fails and the remaining power supply can meet power demands of both server trays, both servers will
continue to run without interruption.
AC redundancy with throttling requires two power supplies to run the z6000 chassis. If one power
supply fails and the remaining power supply cannot support the full load of both server trays, the
servers will throttle using HP power capping technology so that the remaining power supply can
support both trays (Figure 15). Although performance is reduced, the chassis continues to operate
until the failed power supply is replaced. This is the default mode when two power supplies are
installed in the system.
Figure 15. Example of AC redundancy with throttling (default mode)
Running the entire z6000 chassis with one power supply provides no redundancy. The single power
supply will provide power to both trays.
19