Hot-plug power management module
The hot-plug power management module monitors the power subsystem components and regulates the power-up sequence of newly installed server blades and interconnect switches. The power management module is connected with cables to the server blade enclosure management module(s) to facilitate communication of management information, such as server blade and interconnect location, power supply budget, and health status.
Features of the enclosure
The HP BladeSystem p-Class 1U power enclosure provides for power subsystem management with the following features:
•Bi-directional electronic e-fuse provides prompt power up.
•Power zones provide communication and management capabilities between power enclosures and supported server blade enclosures.
•Dynamic power saver achieves efficient power consumption.
•Serial port allows direct monitoring of the 1U power enclosure status.
•Efficient cabling reduces clutter in the area behind the 1U power enclosure.
Bi-directional electronic e-fuse
The 1U power enclosure has a bi-directional electronic e-fuse switch that connects the -48-V DC outputs on bus A to the -48-V DC outputs on bus B. Once a single power supply is installed in a bay on either side of the 1U power enclosure, that side of the power enclosure is immediately powered. Approximately 3 seconds later, the internal electronic e-fuse switch automatically closes, and the other side of the 1U power enclosure is powered as a result. In short, both sides of the 1U power enclosure are powered even if only one power supply is installed, and the 1U power enclosure can operate this way indefinitely. With only one power supply installed, the built-in power management software attempts to limit the number of blade servers allowed to power on. An administrator, however, can override the warning and manually power up the servers.
The only time the electronic switch in the HP BladeSystem p-Class 1U power enclosure opens is when there is a bus short in the power enclosure. If a bus short occurs in the power enclosure, the electronic e-fuse switch quickly separates bus A from bus B. The circuitry within the 1U power enclosure automatically and continuously monitors the faulted side. Once the fault is cleared, the electronic e- fuse switch resets and closes automatically restoring full power to both sides of the server blade enclosure. This is a rare situation.
Power zones
Power zones, when set properly, associate server blade enclosures with the power enclosure(s) that support them. This allows power information and alerts to be sent to the proper power management module or server blade management module when power conditions change. For example, if an administrator removes a power supply from the HP BladeSystem p-Class 1U power enclosure, notification is sent to the affected server blade enclosure in that power zone.
Power zones also define the startup sequence of the server blades when the entire rack needs to be restarted after a total power outage. The server blade enclosures communicate with the power enclosures in the rack to ensure that the server blades and enclosures are powered in sequence, rather than all at once, to prevent overloading the AC infrastructure. The sequence always runs from the top of the rack (power zone 6), top left-hand blade through the top and bottom row of the blades in that enclosure (if ProLiant BL30p or BL35p server blades are installed). The sequence then proceeds
