Storage Area Networks For Dummies®

Chapter 11: Approaches to SAN Management
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Health monitoring
Health monitoring works in conjunction with the agents that I mention in
the preceding section. Because the agent talks to the components, the hub,
switch, HBA, or storage array can give the agent an update on what it’s doing,
how it’s performing, and whether anything is going on that the administrator
needs to be warned about. Then the agent forwards this update to the
management framework so that it can be logged and presented to the SAN
administrator. Any changes in the status of any component on the SAN can
be displayed on the SAN administrator’s console immediately, and then the
administrator can take action.
Levels of monitoring
Health monitoring involves various levels of detail:
✓ At the simplest level, you’re notified whether a component is up or
down (in other words, on or off).
✓ The next level gives some information on whether the status of the component
is good or bad.
A SAN switch, for example, can report that all its internal components
are working properly and that the status is good. If one of its dual power
supplies burns out but the switch is still operating, it reports that things
are bad but that it’s still functioning.
✓ The lowest level of monitoring reports details about a component — in
the case of a switch power supply, for example, the actual voltage level
coming in from the outlet.
All these health-monitoring levels allow you to capture the status of everything
in your SAN without having to run around the computer room checking
the status lights on all your components. Your SAN management framework
takes all these messages and converts them to events or icons on the administrator’s
screen to show you what’s going on.
In-band and out-of-band management
You have two ways to communicate with your components to read their
status or tell them to do something:
✓ In-band management
✓ Out-of-band management
Figure 11-8 shows the two ways that your management server can communicate
with your SAN components.