The fru (Field Replacement Unit) Analyzer

The fru (Field Replacement Unit) Analyzer

The fru (Field Replacement Unit) command (described fully in the fru(1M) reference page) displays field replacement unit analysis on Challenge L and XL, Onyx L and XL, and Power Challenge and Power Onyx systems only. The program considers the hardware state during an error situation and attempts to determine if the error results from faulty hardware. The analysis is based on the hardware error state created in the kernel crash dump. If no hardware error state is dumped, no fru analysis will be displayed.

Each board will be analyzed separately based on the hardware error state. After the analysis is completed, the board (or boards) with the highest confidence levels will be displayed. Currently the boards analyzed include the IO4, MC3, IP19, and IP21. Note that you should also check the version of fru output from release to release, because later versions may report a different analysis.

When a confidence level is displayed, it is based on the amount of confidence that the fru analyzer has in the board listed as being the problem. Note that there are only a few levels of confidence, and it is important to recognize what the percentages mean:

10%: The board was witnessed in the hardware error state only.
30%: The board has a possible error, with a low likelihood.
40%: The board has a possible error, with a medium likelihood.
70%: The board has a probable error, with a high likelihood.
90%: The board is a definite problem.
95%: The board is a definite problem, an exact error match.

There is a possibility of multiple boards being reported, so the field engineer must be cautous when deciding to replace boards. For example, if two boards are reported at 10%, that is not enough confidence that the boards listed are bad. If there is one board at 70% or better, there is a good likelihood that the board listed is a problem, and should be replaced. Boards at 30% to 40% are questionable, and should be reviewed based on the frequency of the failure of the specific board (in the same slot) between system crashes.

The objective is to uncover real hardware problems, rather than to replace boards at random. Each icrash report for each kernel core dump on an eligible system will have a fru analysis in it, which should be reviewed by field engineers before any boards are replaced.

Below are some fru output examples. Please note that each fru command output below comes from a unique core dump. Your output is likely to vary significantly:

>> fru

FRU ANALYZER (2.0.1):

++ PROCESSOR BOARD

++ IP21 board in slot 2: 40% confidence.

++ END OF ANALYSIS

>> fru

FRU ANALYZER (1.6.5):

++ MEMORY BOARD

++ MC3 board in slot 1: 70% confidence.

++ END OF ANALYSIS

>> fru

FRU ANALYZER (1.6.5):

++ CPU slice 3 (CC CHIP)

++ and/or Integral component (A CHIP)

++ on the IP19 board in slot 5: 40% confidence.

++ CPU slice 3 (CC CHIP)

++ and/or Integral component (A CHIP)

++ on the IP19 board in slot 7: 40% confidence.

++ CPU slice 2 (CC CHIP)

++ and/or Integral component (A CHIP)

++ on the IP19 board in slot 9: 40% confidence.

++ CPU slice 3 (CC CHIP)

++ and/or Integral component (A CHIP)

++ on the IP19 board in slot 11: 40% confidence.

++ END OF ANALYSIS

>> fru

FRU ANALYZER (2.0.1): No errors found.