We have two 4500x switches in a VSS configuration running as our core. Recently we started getting some parity errors when we enabled some monitoring/polling of switch statistics. Cisco Tac has instructed us to reboot the core to clear the problem. While we are at it TAC wants to upgrade to the latest (and supported IOS).
Here is my dilemma since it is our core it does all layer 3 routing for the DATA Center our server team is unwilling/unable to shut down and give me a safe maintenance window that would not disrupt operations. Even moving layer 3 to another device is potentially disruptive and not an option not to mention I don't have the ports available to make the connections.
I've looked at the ISSU option but haven't seen anything that makes me comfortable that it will be successful. However, this might be my only option since I can't have an outage.
Any suggestions? has anyone successfully done a ISSU?
