Fabric Manager Users Guide, Version 6.1, Revision A - QLogic

2–Advanced Fabric Manager Capabilities
SM Loop Test
In the default mode, to keep the computations to find loops to a manageable level,
the SM by default uses only a path length of three i.e. three hop loops. Three hop
loops are usually sufficient for checking ISLs when there are external cables
between leafs of the same switch chassis or in other small fabrics but will not be
sufficient for checking all ISLs in large fabrics that involve multiple switch chassis.
For such fabrics the Loop Test Fast Mode should be used.
In typical default mode operations, injecting one packet into each loop is sufficient
to get a high utilization on the ISLs included in the loops.
SM Loop Test Setup and Control Options
There are two ways to run the SM loop test. The test can be run using CLI
commands or can be configured to run using the Fabric Manager Configuration
file. Both of these methods will be discussed in the following sections.
• Run the SM Loop Test using CLI Commands
• Setup the Configuration File to Run the SM Loop Test
Run the SM Loop Test using CLI Commands
Requirements to run the SM Loop Test
• Fabric Manager must be running for host or embedded nodes in order for
the SM loop test to run.
• The Fabric Manager must be master.
• To run in fast mode:
Fast mode must be enabled using the Loop Test Fast Mode command
when starting loop test.
Enabling fast mode will automatically set the path length to 4 and the
inject on each sweep to disabled.
The fast mode can only be disabled by running the Stop command that
stops the loop test completely.
Loop Setup Options
• Set up the path length to set the number of hops that the Fabric Manager
checks to find a loop that leads back to the same switch
/opt/qlogic_fm/bin/fm_cmd smLooptestPathLength
Values are 2-4 with a default of 3
Loop path length is set to 4 for Fast Mode
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