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UCS Upgrade: I/O Path Update 1

Our plan is to have the blade firmware (interface and BMC) upgrade completed by next Wed.  After that it will be time to move up the stack to the I/O devices and manager.  Based on schedules these items will probably be schedule in about 2 weeks.

Impact for the last 3 items:

Based on how the system works, if it functions as designed, we should experience up to one minute loss of connectivity or downtime.  Explanation of the process:

A chassis contains 2 fabric extenders on an A and B side (called FEX or I/O modules).  These are connected to the switch called the fabric interconnect (FI or 6120).  The UCS Manager (UCSM) tool resides on the 6120s and runs as an active/passive cluster.

Summary of Steps for I/O Upgrade:

1.  Confirm all servers have some form of NIC teaming functioning so they can handle the loss of one I/O path.

2.  Confirm the northbound Ethernet connection between the FI (6120) and the 6513 switch have spanning-tree portfast enabled.

3.  Pre-stage the new firmware on all 6 (2 per chassis) FEX modules to be applied on next reboot.

4.  Pre-stage the new firmware on both of the Fabric Interconnects (6120) to be applied on next reboot (I am trying to confirm that you can “activate in startup version” on the 6120).

5.  Reboot only the “passive” Fabric Interconnect (6120).  Note the FEX modules are an extension of the FI (6120), so when the FI is rebooted the connected FEX modules reboot at the same time (meaning all of the B side I/O path is rebooted at the same time).  It can take up to 10 minutes for the full reboot process to complete.  During this time all workload traffic should be functioning via the remaining I/O path.

6.  Once step 5 is fully completed perform a reboot on the remaining FI (6120).  This should be done soon after confirming step 5 has completed.  You want to keep both FI (6120) running the same code version when at all possible.

Again we are told the above steps will most likely result in up to one minute interruption of I/O to the blade servers.  That is if all functions as designed.

Summary of Steps for UCSM Upgrade (Post I/O upgrade):

1.  Perform the UCSM upgrade on the passive FI (6120) device, it will “restart or reboot” the UCSM process NOT the FI (6120).

2.  Perform the UCSM upgrade on the active FI (6120) device, it will “restart or reboot” the UCSM process NOT the FI (6120).

The UCSM can be upgraded and restarted without effecting applications running on UCS; it does not impact I/O functions.

Putting this into perspective . . . what is the disruption when you have to update code on an Ethernet switch or Fiber Channel switch? 

I am real curious to find out if we do have about 1 minute of I/O disruption.  Logically, I would think there is no disruption if you have some level of NIC teaming at the blade and you upgrade the B and then A side.  To be continued . . .

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March 31, 2010 - Posted by | Cisco UCS, UCS Manager | , ,

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