Upgrading Firmware for a 2960 Stack - Behavior when version mismatch

[kkana]

Current FW:  c2960x-universalk9-mz.150-2.EX5.bin

Upgrading to: c2960x-universalk9-mz.152-7.E7.bin

I copied the new FW to all the switches.   I then configured them to all use the new firmware (boot system switch all flash:/c2960x-universalk9-mz.152-7.E7.bin)  .   So I rebooted only the Master switch 1, just to make sure the FW was good.   It then changed the Master to Switch 3, probably due to the FW mismatch.   When I looked at the switch versions this is what displayed:

Switch Ports Model              SW Version            SW Image

------ ----- -----              ----------            ----------

     1 0     WS-C2960X-48FPS-L  15.2(7)E7             C2960X-UNIVERSALK9-M

     2 52    WS-C2960X-48FPS-L  15.0(2)EX5            C2960X-UNIVERSALK9-M

*    3 52    WS-C2960X-48FPS-L  15.0(2)EX5            C2960X-UNIVERSALK9-M

I was worried to reboot the others since the switch that had the upgraded firmware showed 0 PORTS instead of 52 PORTS.  Is this normal behavior when their is a version mismatch, since I did not reboot the entire stack at the same time?   I since went into recovery mode and put back the previous FW on Switch 1.   Everything back working on older FW.  But before I try this again, and reboot the entire stack, I just want to make sure that all 3 are not going to change to having 0 ports vs 52 ports, then have to recovery all 3 switches.

First time doing this so go easy on me. 

[M02@rt37 · Accepted solution]

Hello @kkana,

The reason you have one switch displaying "52 PORTS" and another displaying "0 PORTS" is related to the behavior of the stack when there is a version mismatch during the firmware upgrade.

--Switch 1 (the original Master) successfully upgraded to the new firmware [15.2(7)E7]. It now runs the new firmware, but since it became a standalone switch after the stack negotiation, it shows "0 PORTS" because it's not part of the stack anymore.

--Switch 2 and Switch 3 were running the older firmware version [15.0(2)EX5] and did not get upgraded during the process. They are still part of the stack and continue to function as they were before the upgrade attempt. Therefore, they display "52 PORTS" since they are part of a stack and contribute their ports to the overall switch count.

The version mismatch between Switch 1 and the other switches caused the stack negotiation to determine a new Master (Switch 3) that is still on the old firmware. As a result, the original Master (Switch 1) became isolated from the stack, and that's why it shows "0 PORTS."

To resolve this issue, it's important to upgrade all switches in the stack simultaneously to the new firmware version and then reboot the entire stack together. This will ensure that all switches have the same firmware version, and the stack can function properly as a single unit.

[kkana]

Thank you for your explanation.   I have successfully upgraded all the stacks in our environment.  Hopefully your information will be helpful to others who try to do things wrong like me.  LOL. 

[M02@rt37]

Thanks @kkana for your feddback! Great news!

[Leo Laohoo]

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@kkana wrote:
I copied the new FW to all the switches.   I then configured them to all use the new firmware (boot system switch all

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That is, a minimum, two commands.  I can shorten it all with one command when using the TAR file: 

archive download-sw tftp://<TFTP_IP_ADDRESS>/FILENAME.TAR

The above command will distribute the IOS to all stack members, unpack the files into their respective folders, change the boot variable string and then perform a hash check to make sure the BIN file is not corrupt.