[c-nsp] Cisco Cat4500 Quad Sup VSS ISSU IOS Upgrade

[Garrett Skjelstad]

I know this is an awful answer, but just don't do ISSU on them. 😅

Most of my experiences come from quad Sup8s in the same chassis. We have
been running 3.11.1 for the past 49 weeks, since our last cycle, which is
12/18 months.

The biggest ISSUe (lol) with it, is just the sheer number of jumps back and
forth as you climb the ISSU ladder from a historic release. We have also
found it to be beneficial to do a pre-ISSU supervisor restarts for each
supervisor prior to actually doing the upgrade so as to lessen the chance
of getting 'stuck' in a ISSU-loop with a hung Supervisor. The fact that
4500 sups sit in a 'cold' mode when doing the jumps just adds to the delay,
6500s/6800s are MUCH nicer for this action in the fact they are
'warm(hot?)' and already booted.

A full cold restart of the shelves takes approximately 23 minutes per our
lab units. We have found in some locations that have tolerable maintenance
windows, to load/prep and simply cold start the shelves, instead of a
weeklong of ISSU maintenance windows. Of course, if you patch every 60-120
days as the cadence of each release, perhaps it's more manageable. I read
there are some additional protections and time optimizations in later
rommon versions, but for our use, we just haven't seen the need for a
seperate out of cycle ROMMON patches. We are currently looking at simply
replacing them with Catalyst 9k models.

The 4500-Xs run the same supervisor set and are just as friendly, although
contending with only duals vs quads.

Obviously out-of-band management on all supervisors is a necessity.

YMMV, good luck!
-Garrett

On Fri, Mar 12, 2021 at 12:27 PM Eli Kagan via cisco-nsp <
cisco-nsp at puck.nether.net> wrote:

>
>
>
> ---------- Forwarded message ----------
> From: Eli Kagan <e.kagan at yahoo.com>
> To: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
> Cc:
> Bcc:
> Date: Fri, 12 Mar 2021 20:25:01 +0000 (UTC)
> Subject: Cisco Cat4500 Quad Sup VSS ISSU IOS Upgrade
> Hi all,
>
> I have a rather old Cat4507R+E pair, running on four Sup7e as a VSS,
> IOS-XE version 3.8.8E.
>
> I'd like to understand what's the right way of doing an ISSU on a quad sup
> system. I am planing to go to version 3.8.10E unless someone has a better
> suggestion.
>
> Sharing your first hand experience would be greatly appreciated.
>
> Thanks,
> Eli
>
>
>
> ---------- Forwarded message ----------
> From: Eli Kagan via cisco-nsp <cisco-nsp at puck.nether.net>
> To: "cisco-nsp at puck.nether.net" <cisco-nsp at puck.nether.net>
> Cc:
> Bcc:
> Date: Fri, 12 Mar 2021 20:25:01 +0000 (UTC)
> Subject: [c-nsp] Cisco Cat4500 Quad Sup VSS ISSU IOS Upgrade
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