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February 10, 2006 - page 13 / 238





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Chapter 1

Management, Systems, and IPMI

Management will mean different things to different industries. In simple server systems, a management system may only deal with controlling power on a few servers and making sure they don’t get too hot. In a telecom system, management systems generally control every aspect of the system, including startup of all parts of the system, full monitoring of all components of the system, detection and recovery from software and hardware errors, basic configuration of the system, and a host of other things. IPMI obviously only plays one role in this, but it is a role that must be played. In the past, the monitoring and management of hardware has been done with lots of proprietary interfaces. IPMI standardizes this interface.

Figure 1.1 shows a management system and the things it manages. IPMI fits mostly within the “Hard- ware” box, although there may be other hardware interfaces the management system must manage. The management system ties into all elements of the system and makes global decisions based upon inputs from all parts of the systems. For instance, a server may be overheating or have a low voltage. The management system will be informed of this through the hardware interfaces. It may choose to move the function of that server to another server and bring that server down so it may be repaired. If no other server is available to take over the operation, the management system may look at the severity of the problem, predict how long the system may survive, and let it continue. These types of decisions are called “policy”.

In all cases these events are logged to permanent storage. An operator is informed of things that need human attention. The operator may also issue manual operations to configure and override the management system as necessary.

The operations the management system performs on the system are called “Commands” in this picture. Commands have “Responses” from the system. Asynchronous notifications from the system to the manage- ment system are called “Events”. The system never sends commands to the management system, and the system may perform local operations on its own (such as controlling fan speed) but never perform global operations unless pre-configured by the management system to do so. So the system may perform limited policy decisions, but the management system is firmly in control of policy.


IPMI Implementation

The Management Controller (MC) sits at the center of an IPMI system, providing the “intelligence” of IPMI. It is suppose to be always on when the system is plugged in, even if the system is off. The management system communicates with the management controller; the management controller provides a normalized


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