[OpenAFS] Server upgrade time; which is the right way?

[Mitch Collinsworth]

Greetings,

We're planning an upgrade to all of our AFS servers sometime soon.
We do this infrequently enough that it always makes us nervous.  :-)
As such we'd like to run a plan past the list to see if we're
overlooking something, either obvious or not so obvious...

All servers are currently running 1.2.13.  We're planning to upgrade
to 1.4.4.

The current draft plan goes like this:

1. Take down the database servers one at a time and upgrade the OS and
the OAFS binaries.

2. Take down the fileservers one at a time and upgrade either OS and
OAFS or just OAFS as needed.

There seems to be a conflict of opinions here on whether a rolling
upgrade like this is either a) a non-issue, people do it all the time;
or b) a huge mistake that will inflict serious pain and sleepless
nights because everyone knows we should be taking everything down at
once for a major version upgrade like this.

Comments?

-Mitch