Sun Microsystems Sun Fire V480, Руководство администратора

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Chapter 6 Diagnostic Tools 83
Consider also that some diagnostics must function even when the system fails to
start. Any diagnostic capable of isolating problems when the system fails to start up
must be independent of the operating system. But any diagnostic that is
independent of the operating system will also be unable to make use of the
operating system’s considerable resources for getting at the more complex causes of
failures.
Another complicating factor is that different installations have differing diagnostic
requirements. You may be administering a single computer or a whole data center
full of equipment racks. Alternatively, your systems may be deployed remotely—
perhaps in areas that are physically inaccessible.
Finally, consider the different tasks you expect to perform with your diagnostic
tools:
■
Isolating faults to a specific replaceable hardware component
■
Exercising the system to disclose more subtle problems that may or may not be
hardware related
■
Monitoring the system to catch problems before they become serious enough to
cause unplanned downtime.
Not every diagnostic tool can be optimized for all these varied tasks.
Instead of one unified diagnostic tool, Sun provides a palette of tools each of which
has its own specific strengths and applications. To appreciate how each tool fits into
the larger picture, it is necessary to have some understanding of what happens when
the server starts up, during the so-called
boot process .