Hello,
I have two Catalyst 6880-X in a VSS pair that I need to upgrade to one of the suggested release. I don't have any FEX attached. I'm currently running version 15.1(2)SY6 and would need to go to either 15.2.1-SY6 or 15.5.1-SY1.
I have a maintenance window to do this upgrade this weekend, but I still need to minimize downtime/impact as much as possible.
The documentation I found is a bit confusing, it mentions ISSU and eFSU (enhanced Fast Software Upgrade). I'm not sure what the difference is between the two. I found a compatibility matrix that shows the different minor versions in the same major version and if they are compatible for ISSU/eFSU, but no indication anywhere if you can do a hit-less or minimal downtime upgrade between major versions.
Can someone confirm what the best way to upgrade this pair of switches is to minimize downtime?
Also, is there something that would make it better to go to one version or the other (15.2 or 15.5)?
Thank you,
Luke
