[CentOS] Re: Migration from RH9

Thu Nov 22 16:47:03 UTC 2007
James A. Peltier <jpeltier at cs.sfu.ca>

Leonel Nunez wrote:

> Just like any other migration  do you tests in other machines and do
> parallel tests
> every migration  needs fixes
> Leonel
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I can second this.  I am in the process of migrating 5 research labs 
from Suse 10.0 to CentOS 5 (for various reasons).  The migration has 
been in testing phase for over 3 months and a lot of bugs have been 
found and corrected in that time.

A migration from any OS to another is a very tedious and time consuming 
step.  You will need to work on each part of the migration individually. 
  Start with the services that you are most familiar with or that you 
feel you could learn the quickest.

Setup a machine with CentOS 5 and begin testing that service.  When you 
are confident that said service is operating as it should, shift that 
service from the production server to your testing server.  Let it run 
there for a bit because chances are you'll find bugs and that will give 
you a chance to fail the service back over (if necessary) while you 
correct the issue.

Once you've gotten all the services over to the new box you'll be happy 
to know you did it the "right way" and that you've incurred the least 
amount of pain for you, your fellow workers who work with you and your 

IMHO, you should spend a lot of time testing the Perforce migration, 
followed by your web services.  Migration of any SCM is a potentially 
complicated operation.  I haven't used Perforce before, but be careful.

Secondly, careful testing of your web services is crucial.  You'll most 
likely be upgrading version of Apache, PHP and libraries at the same 
time which can break things like backward compatibility. Samba depending 
on it's function within your institution would be a close third, if not 
a tie for number 2, but that's up to you.

The squid services are probably not all that complicated if they're only 
using a caching server (forward or reverse).

Of course, with proper software unit testing and a bit of elbow grease 
I'm sure it will all go over well.

There are various papers on best practices for OS migrations and various 
other system administrator task on the web just google for migration 
best practices and you'll find lots.

James A. Peltier
Technical Director, RHCE
SCIRF | GrUVi @ Simon Fraser University - Burnaby Campus
Phone   : 778-782-3610
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E-Mail  : jpeltier at cs.sfu.ca
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