Compaq StorageWorks Fibre Channel Troubleshooting Guide

2-4 Compaq StorageWorks Fibre Channel Troubleshooting Guide
Loop Error Histogram Display
The Loop Error Histogram indicates errors detected on the FC-AL when a Fibre Channel Host
Bus Adapter is highlighted. Each bar represents a 3 second period of activity. The histogram
scrolls from right to left. The figure below shows a single error period. Notice that FC-AL errors
do not update the histogram unless a Fibre Channel Host Bus Adapter is highlighted. This
occurs because the server's only view of the FC-AL is through the Fibre Channel Host Bus
Adapter, yielding no real indication of where the source of errors may be. When errors are
displayed, individual components may be disconnected from the FC-AL to determine the failing
cable, GBIC, or component.
Figure 2-3. The Loop Error Histogram, showing a single 3 second error interval
Selecting the server causes the sum of all errors on all FC-ALs to be displayed. Selecting a
different Fibre Channel Host Bus Adapter will display the errors associated with that FC-AL.