End of Life is Meaningless

[Pete Ehlke]

On Mon, May 4, 2009 at 8:28 PM, Mike Hernandez <sequethin at gmail.com> wrote:

> I understand that some systems can't afford downtime for an upgrade, but
> why not upgrade? A few minutes of uptime to take advantage of the hard
> work that the developers poured into making another release can't be a
> bad thing can it? I agree that there's certainly no need to panic, but
> in situations where a little downtime is acceptable I wouldn't opt to
> stay with the old system. Just my .02 :)
>
> --Mike H
>
> Suppose I have a decent sized installation of 2000 machines, and they've
been running SomeOS v4.1 for three years. That's over 2 Million machine-days
of production experience I have with SomeOS v4.1. Sure, there are bugs,
there are behaviors that may not be ideal, and there may be things that I
have to work around. But with 2 Million machine-days under my belt, I pretty
much *understand* those bugs, behaviors, and workarounds, and I can with
fairly significant precision predict and model my installation.

Now, upgrade them. What do I have?

I have maybe eliminated some of the bugs and suboptimal behaviors that I
knew about, but now I have exactly Zero hours of production experience with
my new installation. There are new bugs that nobody knows about yet, new
behaviors to find, and new workarounds to develop. I can't, with any
precision, model my installation, and I can't effectively predict its
behavior.

Management is going to nail me on predictability. They couldn't give a rat's
butt about bugs and vulnerabilities, it's predictability and risk management
that counts.

That's why a lot of people in large installations won't upgrade.
Surprisingly often, there is no compelling reason to, and there are very
significant disincentives. It's by no means clear at all that 'a little
downtime' is the only cost of an upgrade.

-P.