Want ability to restore from failed upgrade.

[Jason Dixon]

On Feb 23, 2005, at 3:30 PM, Chris W. Parker wrote:

> Jason Dixon <mailto:jason at dixongroup.net>
>     on Wednesday, February 23, 2005 12:05 PM said:
>
>> Stop right there.  Yes, you should have backups.  But don't rely on
>> those solely as your backup in case of upgrade failure.  Your focus
>> should be on building a test system and performing the upgrade there.
>> Document and test everything.  Then proceed with your production
>> system upgrade, referring to your documentation and, in the worst case
>> scenario, restoring from the backups.
>
> Yes great idea!
>
> But this would require that I have another computer available with an
> exact copy of my current filesystem on the live server would it not? 
> And
> that's what I don't know how to do. If I could configure an identical
> system to what I've got running live that would be awesome because then
> as you pointed out I could test everything and take notes and then just
> restore if something went wrong and start over.
>
> But I don't know how to make a copy of an fs nor do I know if this is
> even necessary for a test system. I'd think that would it be only
> because if I built a new system from scratch, using the same versions 
> of
> software that is on my live server, it would *still* be configured
> different than my live server (i.e. configuration file changes long
> forgotten about that would not be present on the test system).
>
> What angle should I come at this from?

Your concern appears to be with your application upgrades, as it should 
be.  Ideally, you would create the second system *as* the production 
replacement.  However, assuming you don't have the hardware to allow 
that, then you should just build an identical system (with regards to 
the existing legacy applications), then perform the planned upgrade for 
each part of the system.  Once that is complete, and the steps are 
fully documented (and repeatable), then proceed with the upgrade on the 
production system.

--
Jason Dixon
DixonGroup Consulting
http://www.dixongroup.net