HP hunts down 'rare' BladeSystem problem
Only one power supply domain and if it fails ....
A power supply failure in HP BladeSystem c7000 enclosures can cause the whole BladeSystem to fail, the firm has admitted.
According to an HP advisory note: "HP has identified a potential, yet extremely rare issue with HP BladeSystem c7000 Enclosure 2250W Hot-Plug Power Supplies manufactured prior to March 20, 2008.
"This issue is extremely rare; however, if it does occur, the power supply may fail and this may result in the unplanned shutdown of the enclosure, despite redundancy, and the enclosure may become inoperable."
So, the issue is extremely rare, says HP. But it applies to any HP BladeSystem c7000 Enclosure configured with an HP c7000 Power Supply, if the power supply was manufactured before March 20, 2008. Each enclosure can have up to a total of six supplies.
Our understanding is that all the power supplies in the enclosure are connected together, forming a single power domain. The blades in the system connect to a single power bus. If the power supply fails then all the blades may stop working meaning that all their applications, including any virtual machines, go offline. Effectively, there is a single point of failure and redundancy limitation in the BladeSystem c7000 design.
HP's advisory goes on to say that: "BladeSystem c7000 Enclosure Power Supplies manufactured on or after March 20, 2008, and DC-powered enclosures (typically utilized in an Integrity blade environment) are not affected. To ensure stability of your computing environment, HP is providing a power supply identification utility to enable customers to identify potentially affected power supplies. Supplies identified by the utility will be replaced by HP."
There is more information about the identification utility here. Defective power supplies will be replaced free of charge.
The company provided a statement about the issue: "HP has been made aware of a very small number of incidents involving power supply failures in the BladeSystem c7000 enclosure. Because customer service and product quality are top priorities for HP, the company is working with HP BladeSystem customers to replace all potentially affected c7000 power supplies purchased by customers." ®