32 to 64

[Georgios Magklaras]

On 12/16/2010 05:15 PM, Masoom Siddiqui wrote:
> Hello,
>
> I apologize if this has been answered before. Has anyone attempted to do an
> "in-place" upgrade of RHEL from 32 to 64 bit, either keeping to same major
> version or different? What issues, if any, have you run into?
>
> It appears that there is an upgrade option. Below is from a redhat
> article...
>
>
> In-place upgrades across major releases do not preserve all system settings,
> services or custom configurations...Having said this, there is an upgrade
> option to allow an upgrade without requiring a full reinstall. To get this
> functionality, insert the installation CD of the new version and enter
> either of these commands on the boot prompt:
>
> # linux upgrade
>
> or
>
> # linux upgradeany
>
> Regards
>
> -sid
I have and I think it was RHEL 5.3 32 bit-> 64 bit and vice versa.  
Generally speaking, both of them created problems with third party 
applications that were linked to no standard libraries. In other words, 
if you have 32 bit binaries that you would like to run on the x86_64 
environment, you might run into library problems. Most of the problems 
can be resolved by manually going through the old binaries and replacing 
the library locations in /etc/ld.so.conf, especially as the x86_64 
environment allows you to install the 32-bit version of programs and dev 
libs (i386) from yum repositories.

If you have the option, I would advise you to perform a clean 64-bit 
install from scratch, always keeping an eye on third party apps and 
informing your developers that they might have to re-compile/install the 
binaries of the applications. This works better saving hours of 
resolving lib dependencies.

In these environments, it also helps to install third party apps in non 
/usr or /usr/local locations. In my production systems, I have a 
separate /site/progs volume/partition that includes the bins and the 
associated libs. Most of the times, an upgrade or even a clean install 
option, will give you the option to preserve the partition. That way, 
when I mounted the preserved 32-bit /site partition in the x86_64 
environment, most of the programs worked with minimum tweaking.

GM

-- 
-- 
George Magklaras
Senior Systems Engineer/IT Manager
Biotek Center, University of Oslo
EMBnet TMPC Chair

http://folk.uio.no/georgios

Tel: +47 22840535