[cisco-voip] Questions regarding migration of CUCM 7.1.5.31900-3 to a UCS platform

[Peter Slow]

Hello Everyone,

I'd like your input on a project I'm working on. I have five clusters,
all of which are currently running 7.1.5.31900-3. My goal is to
upgrade each of them to 8.5 running in/on UCS.

My _understanding_ is that I need to get a cluster to at least 8.0(2c)
(which is what actual version, btw?), do a DRS backup, install the
same version in UCS and then restore the backup into the VM.

I was under the impression (until i read all of
http://tinyurl.com/5nuf25 ) that on most I2 servers a Bridged upgrade
is required and this would present an issue, because of time
constraints - The smallest cluster is 9 servers, the largest is 17 or
so and it can take upwards of 10 hours to upgrade a cluster, and about
that long  to actually get everything switched over _after_ upgrading
is complete. (I realize this doesn't need to be a serial process, but
it mostly is at the moment, aside from subs having their versions
switched in pairs.)

The main goal here is to get to UCS, and the team I'm working with
REALLY doesn't want to upgrade the MCS servers one weekend, then move
to UCS servers a week later. (Thus far, I've been telling them that
this is going to be necessary AND that there is NO way to install
7.1(5) in VMWare and _then_ upgrade to 8.x) Right now my only
alternative _seems_ to be getting a CUCM in the lab running 7.1(5),
doing a DRS export to that form the production cluster, upgrading
that, then doing a DRS backup from _that_ to the UCS cluster in order
to get the pre-staged environment up.

There's some additional background below.

Constraints:
The first cluster to be upgraded is composed exclusively of 7845-I2
IBM servers.
In some cases clusters might have  7845-I1's functioning as TFTP or
MoH servers, I am allowed to replace these with I2's prior to the
upgrade if I need to.
76 GB drives and 4 GB RAM in the I2s
The upgrades / reboots etc need to take place during a weekend outage
window that provides me with enough time to roll back if something
awful happens. (I'd like to get everything done in a day, so that I
can spend Sunday troubleshooting if I need to.)

Questions:
* If a bridged upgrade is required, do _all_ servers in the cluster
need to be upgraded, or can I just upgrade the publisher, export with
DRS and proceed from there?
* Can I run 8.5 on my existing cluster of 7845-I2's w/ 76 gig drives
and 4 gigs of RAM? http://tinyurl.com/5nuf25 seems to indicate that I
can, but if it's wrong, I get fired.
* Am I correct about an upgrade from 7.1(5) to 8.x within VMWare not
being supported / possible?

-Pete

Peter I. Slow
AIM: humboldtbgp
Email: peter.slow at gmail.com