Re: RHEL 5.1->5.2 upgrade - part 2 (solved)

["Robert G. (Doc) Savage" <dsavage@peaknet.net>]

On Thu, 2008-07-24 at 21:21 -0700, Roger Hill wrote:
> This is a little bit off topic of this thread, but a little bit not . So I want to just throw this out there . We are planning to upgrade about 100 RHEL-32 bit 4u2 servers to RHEL5.2 -64 bit . We have many various applications on them, but namely IBM Websphere and IBM Http Server, Wily, a few other middleware apps like Stellent , etc.  
> 
>   Which is the easier path ? To upgrade the existing servers, or "build anew" and migrate all of the applications ? 
> 
>   We recently last year did an Oracle RAC migration , and went from AS 3u2-32 bit to AS 4u4-64 bit, where we used the latter method. 
> 
>  I'd like to know the group's experience with upgrading or OS migrations .
> 
> Thoughts, flames ?

Roger,

Yours is a fairly common question with a predictable answer. Here are
three msgs from the RHEL5-list two weeks ago:

***************************************

From: Tim Evans <tkevans@tkevans.com>
Can an RHEL i686 system be upgraded to x86_64 in place, or is a new
install required? Thanks.

From: Jay Turner <jkt@redhat.com>  [QE Director at Red Hat]
I'm sure it can be done, but I'm not sure I would recommend it. I
suspect you'll end up chasing your tail later any time you hit an issue,
not knowing if it's a real problem or just some artifact of the upgrade.
Go with the fresh install. Will save you tons of time in the long run.

From: Mathias Saou
<thias@spam.spam.spam.spam.spam.spam.spam.egg.and.spam.freshrpms.net>
[Builder of many great Red Hat Linux RPM packages]
I've already done it. For having done it, I would really not recommend
it... it's not for the faint of heart! :-)
I posted about it on some list at the time. IIRC it was with a RHEL4
server.
But seriously : Don't do it.

*************************************

Remember that we're still in a transition era where most 64-bit
operating systems are actually hybrids of 32-bit and 64-bit components.
I didn't think it could ever be as bad as things were when the 80386
chip was introduced and we had 32-bit systems still littered with 16-bit
apps & drivers. Believe me it's now far worse, and I'm afraid a lot of
today's 32-bit stuff will be around longer than the legendary Twinkie.

To the extent that some of your systems will be almost identical (e.g.,
load-balanced IBM HTTP servers), they can be quite literally cloned from
a polished master, then trimmed and tweaked for IP address, hostname,
license numbers, etc. If that's not practical, suggest developing custom
kickstart scripts for the core RHEL5.2 OS on each machine, then
individual middleware installs to recreate your current 32-bit
capability. It'll be tedious and time-consuming, but the end result
SHOULD work as advertised. If something doesn't, you'll at least have a
supported baseline to troubleshoot.

--Doc


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