Upgrade IOS on stacked switches

[gauthierv]

I need to upgrade the IOS on my stacked switches and am unsure of the order in which to do it. I have two C3750X switches (my core switches) which are stacked, and then two C2960S that are also stacked. All are currently running version 12.2(55). The recommended versions from Cisco for the 3750X is 15.0.2 (SE7) and for the 2960S, it is 15.0.2(SE6). Since they are stacked, should I upgrade the C3750X switches first, and then the others? I should also add that I will be doing the upgrade via the Cisco Network Assistant. When upgrading, do I only upgrade the master? 

[Rolando Valenzuela]

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

I will go wit the 2960 first.

Remember to have the new IOS image in both switches and not only on the master switch.

Hope this helps.

Rolando Valenzuela

[Leo Laohoo]

The recommended versions from Cisco for the 3750X is 15.0.2 (SE7) and for the 2960S, it is 15.0.2(SE6).

Be very careful when using these specific IOS versions.  

The most stable IOS for the 3560/3750 series family of switches, by far, is still 12.2(55)SE10.  

The most stable IOS for the 2960/G/S series family of switches, by far, is still 15.0(2)SE4.  

I wouldn't gamble my network with any other version.  

PS:  Yes, I tested all these IOS versions you've mentioned.

I should also add that I will be doing the upgrade via the Cisco Network Assistant.

Google the web, you'll notice a number of people running into problems/troubles when upgrading stacks of switches using CNA.  CLI is the best method of doing upgrades because you get to see what's happening (including bad ones) during the upgrade process which you don't normally see when using GUI (like CNA).

[gauthierv]

Thanks for your comments, Leo. You are suggesting two different major releases for the two different switches. I assume that is not an issue to run two different major versions? If I run the upgrade using the CLI, then how do I ugprade the stacks? Do I only need to run the upgrade on the master, or do I still need to do both individually? Lastly, should I upgrade the 2960s first, and then the 3750s (my core switches), or does it even matter?

Valerie