Question on 4500X-32 VSS ISSU

[tahscolony]

I have my two switches prepped to go from 3.7.3 to 3.8.8. Have the image in both bootflash: and slavebootflash: and config-reg set to 0x2102 (actually 0x102 before reload). VSS and NFS are configured, and working, but the stack has not been rebooted in over 3 years since installed, but I do remember testing redundancy.

OK, my question, when doing the standby reload, do all the ports on the standby remain active and passing traffic during ISSU?   Thankfully I do not need to upgrade ROMMON for this upgrade, so wont need to do a hard down on it provided the ports do stay up on the standby switch that is reloading.

[Reza Sharifi]

OK, my question, when doing the standby reload, do all the ports on the standby remain active and passing traffic during ISSU? 

No, once you issue the standby reload, all ports connected to that switch will go down and the primary will continue forwarding traffic. That is why everything needs to be connected to both switches for redundancy to work correctly.

HTH

[tahscolony]

That's what I thought, since the KVM only has one NIC, that is a problem.  Best to just plan for a 15 minute outage and do a shelf reload instead.  The docs regarding ISSU aren't very specific to platforms and lead one to believe that the ports remain active on the 4500X, where in reality that only holds true to all in one chassis with line cards.  Always pays to check first. 

[Reza Sharifi]

Best to just plan for a 15 minute outage and do a shelf reload instead.

I agree with you. Honestly, I have not seen ISSU work as advertised. In addition, with ISSU, you have to reboot multiple times which to me does not make sense at all. With tradition way, you reboot once and you are back in business. If I remember correctly the 4500x switches take less than 5 min to completely reboot.

Good Luck!

[Leo Laohoo]

If the stack hasn't seen a reboot >1 year, then I'd go for a complete "reload" command.

[tahscolony]

Yep, my thoughts too. 3 Years, 5 Weeks and counting. Have not had to reboot them since they were installed. If it ain't broke.... Only reason is because I am upgrading the ASR's there for a nasty hole in the IOS.