CUCM Upgrade 9.1 to 11.5 - Switch Version as part of Upgrade?

[TONY SMITH]

Hi,

I need to plan a 9.1 to 11.5 upgrade, Publisher, Subscriber and Backup Sub.   When I've done a refresh upgrade in the past I have normally (maybe always) set it to switch version at the end of each server upgrade.  However just now I've noticed a couple of things.  (1) When I did a Unity Connection upgrade recently the publisher upgrade refused to switch version until the subscriber had the new version in it's inactive partition.  (2) The CUCM upgrade guide for 11.5 specifies a separate switch version step in all scenarios.

So a couple of questions, firstly does anyone know if CUCM now enforces that same check, effectively meaning that an automatic switch version only works in a single-server install?   Secondly assuming automatic switch version is still possible server by server, is there any particular downside to doing this?

Switching version as each server is upgraded has the advantage that there is only one period of downtime for each server.  In this case for example the Publisher and Backup could each be upgraded with no impact on live call processing.  Then finally the main Subscriber would be upgraded, after hours in this case.

A separate switch version stage means more downtime as the Sub would be out of service while being upgraded, then again as the last stage of switching version.

Comments welcome, Tony S

[Jaime Valencia]

Read here

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/upgrade/11_5_1/cucm_b_upgrade-guide-cucm-115/cucm_b_upgrade-guide-cucm-115_chapter_010010.html

[TONY SMITH]

Hi, thanks for the response.  Yes that's the document I was referring to, you will see that in Table 1 (least time) and Table 3 (least impact) the recommended sequences both have separate switch version stage after all the servers have been upgraded.

[Jaime Valencia]

That is indeed the recommendation, I recently watched a Live session on upgrades to 12.0 and they mentioned the same thing, do not choose the switch version during the upgrade, manually switch once all servers have been upgraded.

[TONY SMITH]

Cheers again.  Did they say why that was recommended?  

In the upcoming upgrade the customer can't have any planned disturbance to the phones until after hours.   So with a separate switch version step we couldn't start the Sub upgrade until that time, and would then have a delay while switching versions on Pub, then Backup before another disruption when the Sub is switched.

In comparison switching as part of the upgrade, Publisher and Backup would all be done and dusted before the start of the change window, with only the Sub upgrade/switch still to be done.  That was how I've done all previous refresh upgrades.  In fact didn't version 8.6 mandate that?  From memory it either switched version even if you didn't select it, or was the option not even selectable?

[Jaime Valencia]

I don't recall them going into any details, but the upgrade methodology has been changing, and there are some changes coming with 12.5+ as well.

Yes, at some point the documentation said that for a RU you had to switch the PUB, then upgrade the SUBs, then switch your SUBs, but as I mentioned, they have been updating the upgrade process and what is currently recommended, is what's in that doc.

You should have no issues if you do it as you want, even if it's not the recommended way.

[TONY SMITH]

Duplicate deleted.  For some reason it kept telling me to correct the highlighted error and resubmit.