How to upgrade C3750X Stack from 12.2.(58) to 15.0(2)

[juergen.fischer]

Hi all,

I've to do a remote upgrade of a 3750 Stack with 2 members. This is the central Core Router of that location.

I've experienced in another scenario that this upgrade from 12.2 to 15.0 reprograms the Microcode and lasted about an hour.

So I'm looking for the safest and easiest way to do that remotely.

I'd like to do one Switch at a time. In case the update fails, I have at least 1 working switch.

And while one Switch is updating the other will run the location !?

Any recommendations are appreciated

[Reza Sharifi]

Hi,

You can't upgrade one switch at the time, because once one switch has a different IOS and rebooted, it will break your stack and cause an outage.  I recommend doing the entire stack at ones.

Also, since you are doing this remotely and going from 12 to 15 is a major upgrade,  you want to make sure the new image is supported on the switch, you have enough memory and flash.  You also want to read the release note for the new version in case of any bugs or feature set that can impact your down time.  If all possible you want to have someone at the site in case the switches need to be cold rebooted by unplugging the power cords.

HTH

[juergen.fischer]

Hi Reza,

thanks for your quick response.

I know that this will not work without an outage - just think how long that might be.

I'll have someone at site or nearby to connect to console - just in case.

What if I do this:

archive download-sw /overwrite tftp://10.134.14.76/c3750e-universalk9-tar.150-2.SE9.tar (No impact so far, new image is prepared for next reload to be activated)

reload slot 1 (Will upgrade Switch 1)
When will Switch 2 be automatically reloaded ?

Or what else will happen to the stack ?

[Reza Sharifi]

Hi,

I personally would not use the "overwrite" statement as if something goes wrong with the new image download or corrupted download, you will not have any image to boot from in case something happens.  I would leave the old image intact. Also, do you know if the archive command is supported when you are going from one major release to another?

Here is good link for the archive command. 

I usually like to have a maintenance window, add the new image to both switches, verify the boot variable, save and reboot the whole stack.

HTH

[Reza Sharifi]

Sorry, I forgot to add the link in my previous post.

here it is:

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/64898-upgrade-3750-stack.html

HTH