Verifying FEX Uplink Pinning in Cisco UCS

In the past I covered how to design for the necessary number of uplinks between the FEX's (IOM's) and the 6100's on Cisco UCS.  Once you have calculated the number of uplinks you will need, how do you know in UCS that the blades have pinned to the uplinks correctly?  (If you don't know what this means, please see my FEX design article listed above, pinning is covered there).  The short answer is that there isn't anything in the UCSM GUI today to tell you this.  The closest thing to a pin mapping output is a listing of the number of uplinks and no errors in the UCSM as an indication of correct pinning.  Maybe I'm too "detail oriented" but I like more information that.  So, off to the command line.

You will need the following commands to verify the status of pinning in UCS.

Step 1 - Connect to the nxos context in the 6100 in question by submitting the command: connect nxos

Step 2 - The command show fex will display the FEX's currently connected to the 6100.  In this case I have two UCS chassis:

Step 3 - Use the command show fex (fex#) details to output the actual pinning relationship.  Empty blade slots are not shown at all and powered off blades are shown in a down status.  In the first example I have 4 FEX uplinks, blades present in slots 1-4, and power applied to blades 1 & 4.  In the second example I have 1 FEX uplink, blades in slots 5-8, and all blades are turned on.

There you have it.  Now you can tell for sure that your blade pinning is correct and this process is also very helpful for troubleshooting as well.