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  1. #1

    Exclamation Fedora is able to detect only 2 GB and not 4 GB of RAM.

    We recently setup a server with 4 gigs of RAM and installed Fedora core 7 32-bit version in it. After installing the OS, I have found that Fedora is able to detect only 2 GB and not 4 GB of RAM.
    i have edit
    (CONFIG_HIGHMEM64G=y). but 3Gb are detected.
    However, the OS still does not detect the 4 GB RAM. Any idea what else can be done apart from installing the 64-bit OS in the system?
    Last edited by lifetimes; 03-26-2008 at 11:45 PM.

  2. #2
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    What type have ram have you installeD?

    dual channel?
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  3. #3
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    Use CentOS or other clone, or run the PAE kernel.
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  4. #4
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    Quote Originally Posted by domainworldaccess View Post
    Use CentOS or other clone, or run the PAE kernel.
    CentOS won't make a difference. It uses a similar .config and has the same issue... How much memory you can see depends on the chipset when you're not running PAE. Some boards will show only 3 and some up to 3.7...

    yum install kernel-PAE and edit your menu.lst accordingly.

    or compile a custom kernel with PAE support.
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  5. #5
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    Centos 32 bits should be able to detect up to 4 GB with PAE, above 4 GB you can use Centos 64 bits

  6. #6
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    Quote Originally Posted by boonchuan View Post
    Centos 32 bits should be able to detect up to 4 GB with PAE, above 4 GB you can use Centos 64 bits
    CentOS's default kernel does not have PAE support, and therefore has the same limitations of any other Linux out of the box. It does, however, have PAE kernels in the repositories. I had to deal with this issue just last week.

    EDIT: Sorry, realized you did say "with PAE". Same story with Fedora, though. And PAE on 32bit will show you up to 64gb as well.
    Last edited by hermetek; 03-27-2008 at 12:36 AM.
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  7. #7
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    Quote Originally Posted by hermetek View Post
    CentOS's default kernel does not have PAE support, and therefore has the same limitations of any other Linux out of the box. It DOES, however, have PAE kernels in the repositories. I had to deal with this issue just last week.
    Actually, 4.x does, but PAE is required in 5.x...
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  8. #8
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    Actually, 4.x does, but PAE is required in 5.x...
    Ah, thanks for the heads up. Didn't know that.
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  9. #9
    Best way is to compile a custom kernel.

    You can get support upto 64GB.
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  10. #10
    thank you all. trouble was processed when install PAE.

  11. #11
    Distros of 32 bits only alow max 2 gb ram . Where is the problem. YOu need recompile the kernel for more of 2 gb ram. if you need any info about thsi contact me. But if you not like recompile and possible crash install 64 bits fedora centos debian what you like

  12. #12
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    32bit Distro's will show up to 4GB of RAM...

    With the HugeMem Kernel installed - I believe it is up to 64GB, I'd have to double check that...

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  13. #13
    what distros centos oonly show 2 gb ram not only 1 mg more . I not thsi very well with the normal kernel and one processor

  14. #14
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    The solution is to rebuild the kernel with PAE to support 4 GB RAM. The other solution is to install the 64 bit version of Fedora which detects 4 GB RAM easily.

  15. #15
    It isn't necessary to recompile the kernel unless you already are using a custom kernel for some other reason.

    Most distributions have pre-built kernels for large memory support. If you just search the repositories, you'll find something.

    Or as people have said, you can install a 64 bit OS.

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