Does upgrading a CUCM cluster publisher affects subscriber?

[rhap4boyz]

We are trying upgrade CUCM cluster from 6.X to 8.X to new servers.  We decided to upgrade the existing servers to 8.X first then do diaster recovery backup and restore to new servers.

My question is when upgrading a CUCM cluster publisher to a later version, will the subscriber continue to service the users?

Once the publisher finishes upgrade, will it be able to service the end users while we upgrade the subscriber?

How much down time should we plan for migration?

[islam.kamal]

Hello

The publisher has to be upgraded first to allow the subscribers to list the upgrade as valid upgrade option. the subscribers then may be upgraded almost at once. in non-business hours you may speed up installation a lot by disabling io throttling.

The time is based on the server specs , i did a upgrade last week from 7.1.3 to 8.0 on MCS 7845 it took around 1:20 hour , but some other time on other hardware it took around 2 so this is the range you are facing.

please find the below link

https://supportforums.cisco.com/thread/2080854

thank you

pleae rate rate if this will help

[islam.kamal]

Hello

I recommend upgrading the Publisher by itself; once the Publisher is has completed, I next recommend upgrading half the cluster in parallel, based on the CM standard Group redundancy configuration; once half the cluster has

been upgraded, I then recommend upgrading the other half.  I’d expect individual subscribers to upgrade in 45-60 minutes (publisher may be twice this).  Most of that time will be spent waiting for the upgrades to complete

Thank you

please rate if this will help

[Ayodeji Okanlawon]

Hi,

Upgrade from 6.X to 8.X can be service impacting depending on what version of 8.X you are going to. Anything below 8.6 can be safely done without affecting service as long as you dont specify switch to new version.

However if you are going to 8.6, then this is a Major Upgrade and the server will reboot many times. This is like doing a fresh installation of 8.6...It does take a long time and it interupt your production service because this is a refresh upgrade.

Another point to  note is this: Does your current server support the 8.X version. It it doesnt then you are looking at a bridge upgrade, which is also service impacting.. Please look at the blog below, it talks about CUCM upgrade best practices.

https://supportforums.cisco.com/community/netpro/collaboration-voice-video/ip-telephony/blog/2013/03/19/cisco-live-london-2013-key-take-aways-part-2

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