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Old 05-20-2009, 09:40 PM   #1
pslim123
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re: Installing 32bit linux to 64-bit machine?


Hi Guys,

Wonder if anyone can help to answer this question. Basically I need to know whether I can run 32-bit RHEL4.6 in x86-64-bit Server and what are the main things that I really to look into when deploying 32-bit linux to 64-bit machine?

If yes, when i install additional program into 32-bit linux on 64-bit machine, will there be any issue?

Thanks.

regards,
Keith
 
Old 05-20-2009, 10:42 PM   #2
Quakeboy02
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I'm running 32-bit Lenny on an AMD Phenom. There were no install issues. I don't believe there are any 64-bit chips actually in the wild, so it should just be a matter of installing and running. Except, that you do mention "64-bit server". If that means that it has more than 4GB of RAM installed, then you will need a PAE enabled kernel to make use of it by the kernel. Your apps will still be limited to a 4GB memory footprint.
 
Old 05-21-2009, 06:55 AM   #3
johnsfine
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Quote:
Originally Posted by Quakeboy02 View Post
If that means that it has more than 4GB of RAM installed, then you will need a PAE enabled kernel to make use of it by the kernel.
Even if you have just 4GB of RAM, you need a PAE enabled kernel to make use of all of it. The max ram without a PAE kernel depends on some details of your BIOS. It is often 3.25GB, rarely less, sometimes more, but never very near a full 4GB.

If you have more than 8GB of RAM with a 32 bit PAE kernel, you are likely to run into problems caused by the normal 1GB limit on kernel virtual memory. I don't know the details of the work arounds if you really need them. Most people with more than 8GB of RAM should choose a 64 bit kernel and avoid those issues. Tell us if you have more than 8GB and have a good reason to use a 32bit kernel. Maybe someone who knows those details would explain.

I think some Red Hat versions also have license restrictions on the amount of RAM, so they may give you access to less than the total your system physically has. I don't know those details either.

Other than the above, there should be no problems. The 32 bit kernel will not care that the CPU could have run 64 bit. Any x86_64 CPU can operate as a totally functional, compatible and efficient 32 bit x86 CPU. Once you are running a 32 bit kernel all installation and operation of other programs will act just as it would have on a 32 bit CPU.

Even if you have too much ram for a non PAE kernel and/or too much for some Red Hat restriction, that won't stop the system from working. It would just give you use of less than all of your ram.

Last edited by johnsfine; 05-21-2009 at 06:56 AM.
 
  


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