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Old 08-29-2008, 10:59 AM   #1
dipuasks
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Exclamation How to install SMP Kernel


I just installed CentOS 5.0 on a Pentium Dual Core server. I have 4GB RAM but Linux detects only 2.9GB. Earlier I had solved this problem by installing SMP kernel so I want to do that now. But after a lot of searching, I couldn't find a smp kernel.

I tried installing through yum but no luck. May be my command is mistake.

Kernel version:
2.6.18-92.1.10.el5

Any ideas where can I get a smp kernel or what should be the exact yum parameter?

--Dipu
-------------------------------
The nice thing about Windows is - It does not just crash, it displays a
dialog box and lets you press 'OK' first.
 
Old 08-29-2008, 11:32 AM   #2
zQUEz
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if you type `uname -a` I think you will find you already have the SMP kernel installed. This is the default with RHEL5.x (which is what Centos is built from).

With that said, I also have the same version Kernel installed (RHEL5) and it detects atleast 8GB.
 
Old 08-30-2008, 06:48 AM   #3
dipuasks
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Oh ok, I was just checking uname -r.

This is my uname -a:

[root@axon ~]# uname -a
Linux axon.exa.mumbai 2.6.18-92.1.10.el5 #1 SMP Tue Aug 5 07:41:53 EDT 2008 i686 i686 i386 GNU/Linux

So this means I have SMP kernel right? But then Why it is not detecting 4GB RAM? It only detects 2.9X GB


--Dipu
-------------------------------
The nice thing about Windows is - It does not just crash, it displays a
dialog box and lets you press 'OK' first.
 
Old 08-30-2008, 07:03 AM   #4
pinniped
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You probably installed a 32-bit system and did not put in the bits needed to address 3GB+. I can't even remember the name of that bit now... but you can search the previous posts for memory-related questions.
 
Old 08-30-2008, 07:06 AM   #5
zQUEz
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Well by default Linux will detect all the RAM you have on your system. So there isn't a "special" parameter or whatever for 4GB RAM. What are you looking at that tells you, you have 2.9GB of RAM? Are you running a XEN kernel? What hardware specs do you have? Can you boot this same hardware with a another distro (Fedora or whatever) via a live cd and it is fine? Are you BIOS settings correct? What does `dmidecode` tell you about the installed memory modules you have?
 
Old 11-10-2009, 04:25 PM   #6
fachamix
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you are looking for PEA

Ubuntu PEA

Kernel PEA

PEA support
 
Old 11-10-2009, 04:26 PM   #7
fachamix
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sorry

its PAE instead of PEA

https://help.ubuntu.com/community/EnablingPAE
 
Old 11-10-2009, 04:42 PM   #8
johnsfine
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Notice the date on post #5 of this thread.
 
Old 11-10-2009, 04:55 PM   #9
salasi
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Quote:
Originally Posted by pinniped View Post
but you can search the previous posts for memory-related questions.
Or, as it turns out, future posts. Lots of future posts.

Just for reference, PAE was the 'address more ram in 32 bits' option and it has nothing, fundamentally. to do with SMP, but, early on, some distros may have bundled their SMP and PAE functions together and called it SMP, for convenience. These days, SMP is the default in most circumstances and the name SMP has more-or-less gone from mainstream distros.
 
Old 03-09-2010, 11:19 AM   #10
rgustafson
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SMP Update

Hi... It's 2010 and I'm adding to this extended discussion...

Usually I update CENTOS 5 using 'yum upgrade kernel-smp' but I just tried that on a new P4 HT box today, and it tells me 'Error: No Package Matching kernel-smp'. I ran 'uname -a' and it responds with:
Linux mysub.domain.net 2.6.18-164.11.1.el5 #1 SMP Wed Jan 20 07:39:04 EST 2010 i686 i686 i386 GNU/Linux

That indicates the SMP kernel is installed, correct? So why wouldn't the update work? Thanks!
 
Old 03-09-2010, 04:12 PM   #11
fachamix
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check this out: http://wiki.centos.org/FAQ/CentOS5#h...07a4bd3ea175b7



there is no "kernel-smp" for CentOS 5, that was used under 4.

if your machine has a large amount of memory, install kernel-pae :

http://en.wikipedia.org/wiki/Physical_Address_Extension



kernel-pae
>
> [root en laptop ~]# yum list kernel*
> Loading "installonlyn" plugin
> Setting up repositories
> Reading repository metadata in from local files
> Installed Packages
> kernel.i686 2.6.18-8.1.4.el5
> installed
> kernel.i686 2.6.18-8.1.6.el5
> installed
> kernel-headers.i386 2.6.18-8.1.6.el5
> installed
> Available Packages
> kernel-PAE.i686 2.6.18-8.1.6.el5 updates
>
> kernel-PAE-devel.i686 2.6.18-8.1.6.el5 updates
>
> kernel-devel.i686 2.6.18-8.1.6.el5 updates
>
> kernel-doc.noarch 2.6.18-8.1.6.el5 updates
>
> kernel-xen.i686 2.6.18-8.1.6.el5 updates
>
> kernel-xen-devel.i686 2.6.18-8.1.6.el5 updates
>
> [root en laptop ~]#





take care
 
Old 03-09-2010, 11:09 PM   #12
rgustafson
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Thank you for your reply. I wasn't aware of this change. With my 2 gig of RAM, I won't be needing PAE!
 
  


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